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Note: the answers to questions presented on this forum are offered as suggestions only. Any action taken as a result of reading something here is at your own risk. If you are building or repairing a septic system, you must meet the regulations and laws of your local and state health departments. The Think Tank is a forum intended to broaden the discussion concerning septic design. It is not intended as a substitute for septic design on your property. All questions subject to publication. Questions with attachments will not be read.
Looking After Your Septic System
When Do I Switch to My Back-Up Drainfield? When to Pump the Tank? What About Tree Roots and Septic Systems? Should I get Help with my Leaking System?
Adding To an Existing Septic
I Want to Hook Up An RV to My System Is My Septic Tank Too Small? Two Septic Tanks Needed In Large Home? Placing Dirt Over Existing Septic
Building Near the Septic System
Adding A Pool in the Septic Replacement Area Is It OK to Cover the Drainfield With a Pool Deck? Tank Under My Floor
Site Evaluation (or Perc Testing)
High Water Table Problem Adding A Pool in the Septic Replacement Area
Simple Failures
Help for a Slow Drainfield Ugly Failure Repair Strategy in MA My Tank Leaks Help-My Yard is Sinking!
Legal Issues
Illegal Septic Tank Going In Next Door? Septic Systems Causing Illness? Next Door Lot Drainage Problem Moving a Drainfield Off My Land Is Having an Off-Site Drainfield Wise?
Health and Odor Problems
Septic Tank Under the Floor smells Septic Systems Causing Illness? I'm Pumping Sewage Into the Bushes
Mound Systems
Can I Change My Mound's Shape Peat Filter vs. Mound System Frozen Mound Failure How Do I Hide My Mound? How Long Does a Mound Last?
Sand Filters
My Sand Filter Failure is a Mystery Bad Repair Required Sand Filter My Sand Filter Makes Me Nervous Sand Filter Failure Wrong Spec for Sand Filter Sand?
Pumping Issues and Sewer Slope
Pumped the Wrong Tank Difficult Septic Tank Pumping Job Long Sewer Line Runs Uphill What is Max Slope to build Septic?
Freezing Weather Issues
How Can I Get Rid of the Check Valve in my Pressure System? Use of Check Valve causes Freezing Problem
Preventing a Frozen Sewer Does a Weep Hole Protect the System from Freezing?
CAD Drawing Questions
Can't Open CAD File How Good is the Rhinoceros CAD Program? How Do I Get Started in CAD? I Want to Convert CAD File for the Web What CAD Program Do I Need? Will the new 2006 Pressure CD Work in My Area?
Green Septic Questions
Is there a Solar Septic System? What Exactly is a Cess Pool? Watering Plants With Greywater Can My Composting Toilet Qualify Me for a Reduced Drainfield?
General Technical Questions that do not Fit Other Catagories
How Does Water Flow Inside My Septic System? Good Web Site Winery Septic System Vaults, I Need More Info Are Pressure Designs Available on Your CD?
Subject: Will Your Plans Work in My County?
Posted: Randy October 20, 2005
I design septic systems for my company that installs them here in the lake district. My county health department now allows the use of Infiltrator type vaults in septic systems. Local installers are all starting to use this product a lot. My boss wants me to get up to speed with the vaults. I have been trying to find AutoCAD construction drawings and design details all over the Web and it looks like you guys have a great product.
My question is this: With so many ways to skin a cat, how do I know that your plans will be approved here?
Randy, It is a mystery to me that there has never been a graphic standard for septic systems in the USA. Every one of the thousands of counties in all the states seem to have their own rules. At one time I searched for standard graphics and finally just decided to produce my own.
We now have a uniform building code even though people always said that places were too different from each other to apply uniform building rules. Health departments and state health boards hang on tightly to their authority and love to make up odd rules as anyone in the business is aware. The benefits of a uniform graphic standard would seem to outweigh the problem of needing special laws for special areas. We just happen to work in a field that is slow to embrace change in this area. We can buy different cars for rough roads or long commutes that conform to uniform crash standards. It should not be that much of a problem, and I think things will change soon.
The septic business now recognizes many proprietary components whereas in the past, only a few special items ever found their way into septic systems. A good example of such products driving the industry are the PVC vaults and smart panels. They have become a standard in most areas even if for some reason local health wants to keep them out. My standard CAD drawings available on this website recognize this and are producing a standard design set that works for most counties and parishes using readily available parts. Being CAD drawings, they can generally be easily modified to conform to local health rules of trench depth and lateral spacing and the like with a few small changes.
I have been selling standard plans for over three years, and my customers have found that local health departments are quite happy to have a uniform drawing standard. After all, if the vaults are approved in an area, should local health concern itself about how laterals are mounted inside the vaults? You will find that my instant drawing library will save you tons of drawing time in your work and the ideas are well tested in the field across the country. I am sending you a free Pressure CD to try.
Subject: Why the Weep Hole on the Transport Line?
Posted: Darryl May 23, 2005
Your site is very informational and I have returned several times to learn more about septic systems as I have experienced a few issues of my own lately.
I have a question about my pump tank plumbing that I am unsure of. I recently repaired the line exiting my effluent pump tank that was leaking and causing water to pool above the tank. After I repaired the line I watched the tank pump itself empty and noticed that inside the tank the PVC pipe had a small hole in it that would spray inside the tank when the pump was on. I think that the hole is intentional (allow line to drain back into tank, prevent freezing in winter, etc.) but wanted to check with a professional. Is the hole in the line intentional or should I replace the line? Thanks Darryl
Darryl, This is an important issue and one that is not often discussed or well understood. I design all of my transport systems to drain back completely into the pump chamber but not through the "weep hole" that you saw. The hole at the bottom of your transport line is what you guessed, a squirt hole to drain the transport line after the pump shuts off. Unfortunately, this hole squirts sewage around in the pump chamber whenever the pump is running.
Draining the line between doses of the pump prevents freezing of the line in cold weather. This system of draining the line back into the pump chamber not only makes a mess, but spraying sewage causes the formation of Hydrogen Sulfide gas which is highly corrosive. Parts of the system exposed inside the pump chamber and the walls of the chamber itself are vulnerable to deterioration from this gas.
Because I work in central Washington State where on rare occasions temperatures can dip below minus 20 or more, transport lines must be freeze protected. Simply burying the lines below frost depth works fine for water systems, but parts of a septic system work better when things are shallow. The pump chamber for instance is hard to inspect and service through a small deep access riser. Also, at the other end of the system the drainfield works better when very shallow. The drainfield must be built within three feet of the surface in most states anyway.
Therefore a well designed septic system is likely quite shallow, and draining the lines between doses is the best method of protecting the lines from frost. Some pump manufacturers actually require a check valve with the use of their pumps, and some pumps have check valves built-in, so the weep hole is the only method available to drain the transport line in these cases.
Long transport lines may not drain back through a small hole in time for the next dose, and calculating such a system although not impossible becomes much more difficult and theoretical.
Systems designed by Eco-nomic, known locally as "GTO Systems", only specify pumps whose manufacturers stand behind this practice of draining back through the pump. I am willing to share my list of acceptable pump manufacturers with other professionals because unbelievably, many manufacturers that I have contacted are unaware of this issue at all or are unwilling to designate someone with authority to even discuss it with me. Some manufacturers insist on a check valve in the system because they are worried that with multiple pump systems, one pump can be driven in reverse by another sharing the same transport line. This will ruin the pump seals but we are talking here about drainback through the pump, not driveback. GTO Systems always use dedicated transport lines to the drainfield from all pumps and check valves if needed are located at the drainfield, so driveback is not an issue.
So a good way to check if your system large or small is well designed is to look for a check valve, or any valve in the pump chamber. Poorly designed systems often use ball valves or gate valves to regulate the output of a pump instead of having the designer calculate the output. Always use design to control output of a pump instead of a valve. When a system has problems, the first thing people do is twist the valves, messing up the precious settings.
The technology of septic design is changing as fast as the high-profile computer industry. But as with septic systems themselves, this technological revolution is practically invisible. The manufacturers who are knowledgeable about their own products and are responsive to the needs of designers in a changing industry will be around in the future, as will the septic systems that result. The others will not.
Subject: Sewage On the Ground in a Losing Battle With the Septic System
Posted: Jennifer March 20, 2005
Hi, I have a question and hope that I am making sense. We live in a home that is 51 years old. About 12 years ago we had a new drainfield put in our back yard but did not replace the tank. About three years ago my husband dug up part of the yard because our tank was getting full and he capped one of our drainpipes because he swore there was just tons of groundwater pouring in. Since then about once a week, he puts a sump pump into the tank and pumps the tank into the way back of the yard that has tons of bushes. So, my question has always been what if we got a new tank and hooked back up the pipe that was capped? Do you think that would help? I can't imagine we need new fields put in after just 12 years, but I do know our tank is only 500 gallons. Our kids are now older, barely home so the usage is not what it was years ago, but I'm trying to figure out the problem and if ground water can actually be a culprit in this. How would you fix a ground water problem? And do you have any thoughts on whether just a new 1,000 gallon tank and hooking back up the pipe (or not) would help? Thanks! Jennifer
Jennifer, What pipe was capped? If it was a drainfield line, it may compromise the function of a system already in crisis. From your description, your system may be failed and not taking any more water, or it may be waterlogged from ground water, or both. Any groundwater leaking into a septic system is bad, and should not be tolerated. It will eventually kill even a healthy system.
Simply capping one of the lines in the drainfield is not a sufficient fix. A new tank sealed to the surface would likely help, but the drainfield is usually close enough to the tank, so that measures must be used to protect both the tank and the drainfield from groundwater. The fix is usually in the form of improved drainage. You may need a French drain, or other drainage design, given that you have sufficient slope, and a place to drain the water away to that is not into a neighbor's yard. You will likely have to replace the drainfield as well, but a local expert should check your system and get to the bottom of your problems.
Pumping out a septic tank yourself onto the ground surface is not safe, and doing it that often is simply living in denial. I would get expert help right away before local health finds out. If they do, you and your family will have to move out till it is fixed.
Subject: How Long Will My Mound Last Before it Dies?
Posted: Jeff March 20, 2005
Approximately how long does a typical sand mound system last with proper maintenance? I know of in ground systems that have gone 30+ years, but I hear sand mounds don't last nearly as long. I am buying a house with a sand mound and was wondering how long it may be before it needs to be re-done. Thanks, Jeff
Jeff, Research indicates that conventional pressure systems survive about as long as conventional gravity systems. Mounds and sand filters have a higher failure rate with mounds kind of at the bottom of the list. However, I know of areas with excellent installers and smart designers where mound failures are practically unknown.
I believe that if you started with a good designer who could perform an excellent site evaluation and then create a design with the correct features such as a large number of small orifices in the laterals, lateral lines spaced at no more than eighteen inches apart, careful sand selection and you then had the thing constructed with the best installer you can find, and with attention to water use in the home and few serious overloads (elapsed time meter on the pump mandatory and you must know how to use it) you could expect thirty years from your mound or more.
One disadvantage mounds have over most other systems is that the drainfield is by design above ground. Severe winters will therefore be harder on mounds and certain special precautions must be taken. Check this message, and also check this website on questions about sand filters, because many of the same issues apply
Subject: Is an Off-Site Septic System OK?
Posted: Gary March 20, 2005
I’m looking at building a house and the lot that my wife and I want to build on has an off-site septic system. I’m guessing they used the off-site system due to the fact that the back yard has a 20 to 30 foot drop off.
Now to my question. What are the pro’s and con’s about the off-site system? Should we pick another lot that has the system on site? This is the first time I have heard of an off-site system so any help would be great. Thank you Gary
Gary, If the septic system is off the property, you need to confirm that the system and its replacement area are contained in a "perpetual sewage easement" that is tied to the lot that has the house on it and that the sewage easement is listed on the title. Mention this to the title insurance people at the time of the sale and make it a condition of sale that this issue is resolved to the satisfaction of your lawyer.
Off-site septic is rare and the only way to go in some special cases. The easement area will never be usable by the other owners for anything. If the other property is sold, you may have to be prepared to introduce yourselves and educate the new owners. I would also check with a qualified designer before the sale to ensure that the drainfield property is technically OK and large enough for the house you want to build, and that it meets all local regulations.
Subject: We want to Build a Pool in our Back Yard, But the Replacement Area is in the Way
Posted: Mark March 18, 2005
My wife and I are in need of some advice. We want to install an in-ground pool. However, it would sit dead center in our ‘repair area’. We asked the county to come out and move the repair area to the front yard. They said that this was not possible due to the soil not being good enough. Our idea now is to dig up the front yard however deep we need to, to replace the ‘not ok’ dirt with better soil. Is this at all even plausible? And if not, what would some of our other options be? Are there people or contractors that can move the septic lines to other areas of the lawn? Are there other types of septic systems that would take up less space? Any advice is welcome. Mark
Mark, The replacement area by law must be identified in the design. It is a spot to rebuild the drainfield when the original drainfield gives up the ghost. This area generally can not be reduced, even though more compact systems are available. Most health jurisdictions are extremely conservative in this. What you are proposing is known in the business as an "expansion". If what you learned about the soil on your property is true, you would be ill advised to trade a superior replacement area for a poorer one regardless of the anticipated value of the pool as an improvement, or for any other reason.
Given that you have soil on your property that is that different over a short distance between the front and rear of the house, plus you do not have enough room in the rear yard for both a pool and a replacement drainfield, It is likely that you already have a "difficult" site. You should be extremely careful to protect your replacement area. I get mail constantly from people who are living with a failing system and are without adequate replacement area, and in this business there is really nothing sadder.
Further, no, you can not disturb or replace soil and expect it to function as a septic drainfield. You will find constant references to "undisturbed soil" throughout all sewage regulations when it comes to both drainfields and replacement areas, they are not kidding.
Subject: Tree Roots are Invading My Drainfield
Posted: Ron March 18, 2005
I have roots growing in my leach field and would like to know if there is a safe effective way of having them mechanically removed? Thanks Ron
Root control in the septic system is sort of a tough question. Mechanical removal of roots in the drainfield pipes will likely cause more damage than the roots themselves. If the tree roots make it into the septic tank however, you would be surprised how quickly they can create a huge snarl-up.
In the tank, physical removal is mandatory, and pipes leading into the tank should be excavated and sealed to prevent future intrusion. Plastic pipe and glued joints are impervious to tree roots. Copper sulfate is the most common cure in the drainfield. This paper Controlling Tree Roots in Sewer Lines with Copper Sulfate from Oklahoma State University is an excellent source on how to apply this chemical compound.
Some health departments suggest horizontal separation between tree canopies and drainfields of at least 25 feet with water loving trees like willows and poplars even further. Some experts are not convinced that trees in the drainfield area all that harmful, and I tend to agree with them. Keep trees away from the tank though.
Subject: I Have a Back-Up Drainfield, but When Do I Switch?
Posted: Paul Murfreesboro, TN August 4, 2004
We just moved into an 18 year old home this month and have discovered a septic problem. The system has a solids tank that drains to a effluent tank on one side of a bull-run valve and a back-up drainfield on the other side of the bull-run valve. The effluent tank is emptied via a pump to the primary drain field which is about 200 ft away and 10-15 ft above the effluent tank. I have noticed effluent backing up at the outlet pipe and running out onto the ground at a point just outside of the effluent tank (right as it enters the pipe going up to the drain field). Is this a sign of drain field failure? I had the solids tank pumped today and turned the bull-run valve to the back-up drain field. Should this "fix" the problem and how long should leave the bull-run valve turned to the back-up drain field? How will I know if there is a problem with the back-up system? Thank you for any assistance you can provide. Paul
Paul, Your "primary" drainfield may be a replacement system. The "backup" is probably the original system. Your "primary" may be failed. I would go to the "backup" for at least 6 months - a year better. The only way to monitor either drainfield is with ports. I would put ports in both drainfields to check effluent levels in both drainfields at all times and keep the effluent depth at the floor of the drainfield at no more than 2" until both systems have stabilized.
You are correct that the primary is a replacement system. The "back-up" system failed and the original home owners installed the now "primary" system after the failure. How do I install ports? Is there information on them on the site? Is switching back and forth between the two systems regularly the way to manage this type of system? Paul
A port is simply a 4" diameter pipe that has a cap on the top and is open on the bottom (no slots or holes in the side needed) and sits somewhere within the footprint of the drainfield. The trick of placing a port in an existing drainfield is not to hit a pipe as you dig. Use a small shovel or a post hole digger and go slow. When you hit the filter fabric, or other drainfield cover, cut a hole and keep going. Place the port to the bottom of the drainfield rock and no further (one foot below the top of the drainfield rock generally). Now you have a window into the drainfield. One or two inches or less is the normal depth of effluent at the bottom of the port. The spare drainfield should be dry. Do not switch until the spare has been dry for a few weeks. Switching back and forth is the only way to manage this system because you are having trouble with both systems. If the whole thing stabilizes and you are not using too much water in the home, you should be switching drainfields once per year. Look at the image on web-site of the squirt test. This drainfield has six ports, one at each lateral end. The ports also act as a risers for the laterals so that periodic squirt tests can be performed.
Fantastic info. Thank you very much for taking time to reply with such detail. I will install the ports this weekend. Thank you again, Paul
Subject: My Sand Filter is Dying - Why?
Posted: Ron July 28, 2004
I have a sand filter that is one year old and has biomated. The BOD samples taken by the installer have come back 485 and 530. I took a sample and had it tested and it came back 270. Tests for grease and oils were not out of the norm. We do not have a disposal and our eating habits are healthy. What could be causing the problem?
What is the daily flow through the filter. Do you have an elapsed time counter on the pump?
I believe we are pumping no more than 385 gallons a day .The installer said he cut us back from somewhere a little over 400 down to 325 then raised it up. He claims that biomatting is the problem because of high BOD. Could high water usage cause a high BOD. We do not have a dishwasher or disposal that might contribute to the high level. Thank you for your time.
High water usage can cause high BOD - high water use reduces the time for solids to settle and cause carry-over into the sand filter. What kind of septic tank filter do you have in the system - a cartridge type filter will help a lot - also high loading due to surges can cause problems as well - checking the numbers weekly can give a false impression of daily loading - I would check both the pump and the ports daily in the evening for two weeks and keep a log book. Low depth in the ports soon after high water use indicates high transport time through the filter and comes just before failure. This check may be futile if the filter is gasping anyway.
If the above check for surge and filtering is OK, there are two places to go. First, the quality of the filter sand should be checked. Don't forget eye protection and latex gloves before digging in a sand filter or any wet part of the septic system. Take a sample and dry it out in the sun until powder dry. Take the sample to a lab for a soil analysis, or borrow a sieve set from a contractor or take the sample to local health to check for quality. The sand requires a mix of sizes of particles and more coarse particles than one might expect. One common cause of failure is the use of "natural" (low cost) sand from a private, rather than a commercial pit-run source.The second thing to check is the design of the lateral network. I design sand filters with lateral spacing and orifice spacing no greater than 1' 8" (1' 6" is even better). This yields 36 orifices per bedroom. Your filter should have at least 100 orifices total if you are pumping 360 gallons per day and these orifices should be evenly spaced on a grid. Orifices should be no larger than 1/8 inch diameter. If your lateral network is spaced wrong or has too few or wrong size holes, you may have to replace it and perhaps buy a new pump. Distribution must be even across the filter. Perform a squirt test by replacing end caps with ones with orifices to match those in the laterals. The lateral end with the highest squirt height should be no more than 20% greater than the lateral end with the lowest. Remember to measure squirt height from the top of the lateral pipe to the top of the squirt stream.
Good Luck - let me know what you find.
Subject: My Neighbor's Tank is a Little Too Close
Posted: Brian April 8, 2004
Are there any distance-to-property line requirements for installing a septic system/tank? We have a new house being constructed next to us and they are installing the septic tank right along the property line. Thanks, Brian
Brian, Every state and local jurisdiction have slightly different regulations - this site does not compile local regulations from the thousands of counties throughout the USA, in fact I doubt that anyone does - septic regulations are regional and local, subject to change and numerous.
However, the most common setback between the tank or drainfield and a property line is 5 feet. Further, the setback from a line of easement is generally 5 feet as well requiring a normal side yard setback of 10 feet given a usual 5 foot side yard utility easement. Local health can in some special cases waive the side yard setbacks with proper reasons - however, if the setback is a state law, the state must approve the waiver (usually a lengthy process that most state health departments are reluctant to do). I recommend you obtain a copy of the neighbor's septic design from the local health agency and see first if the design includes any relaxations or waivers of setback to property lines or easements. This design is a public document and like tax assessment, any septic design must be made available for any property, although you may have to pay for copies. While at the health department, get a copy of their ordinance to check what the requirements are for setbacks to property lines. Now you can determine if the neighbor's septic system is legal.
Subject: What is the Test for a Healthy Drainfield?
Posted: Steve New Jersey April 8, 2004
First of all, Great Site & answers to FAQs. My question is regarding a septic system inspection. We are selling our home and the inspection was done the middle of March while snow was still on the ground and melting. When a test is performed what test criteria is used for saturated soil? I was not around for the inspection, however, one of the comments on the report was that there was 3 ft of saturation - How was this ascertained? The back yard in general was very soggy and the leach field did not appear different from the rest of the yard.
I am kind of new to this, however, it looks like a major repair if the leach field is not allowing the correct saturation through the field soil. My lot is about an acre in size, 4 bedroom, 2.5 bath, built in 87, I have lived here 10 years with 4 people, now 3. Down-sizing is why I'm selling and finding out this wonderful info. I did have the soil fractured and have also periodically flushed various products down the toilet, and I have no smells, no toilet back-ups, but, do have a greener area over the field - not soggy though. Have had it pumped every two years & use bio degradable soaps and paper. Sorry for the rambling! Thanks! Steve in NJ
Steve, Septic system inspection is a great topic with many myths out there. As you have learned, septic system inspection uses a lot of judgment. An experienced inspector has seen many failed drainfields. Besides the customary tank pumping and inspection of internal baffles, a thorough septic system inspection should include a check for saturated soil. A failed drainfield is almost always associated with saturated soil close to all of the drainfield trenches. The true test of saturated soil is usually done in one of three ways:
First, and easiest, inspection ports have been provided in the drainfield area during drainfield construction. The inspection ports not only provide access to the drainfield, but they show on the surface exactly where the drainfield is. A port is simply a vertical pipe with a cap, placed in the drainfield down to the bottom of the trench. Every available cap is removed and a piece of lath is dipped to the bottom of the port. Two inches or less of water is normal in the bottom of the drainfield. Anything over four inches means the drainfield is being stressed. High water in the ports indicates the need for a later check after the drainfield has rested for a day or so to make sure that the high water is not a normal spike following a busy weekend.
Secondly, if no ports are available, a test pit is dug next to the drainfield with a backhoe (after making sure no underground utilities are in the area), and soil samples are taken down through the soil profile on the walls of the pit. This pit can not always be dug without damaging the drainfield so some repairs may be necessary following the test. The test for soil saturation is to squeeze a sample of soil in the hand (latex hand protection of course) and attempt to get a drip of water. Water dripping from soil is a saturated sample.
The third method is to use a hand auger to extract samples from the area below the drainfield for testing. This test is the least reliable, because the inspector can not be sure that the drainfield has been located. The superior backhoe test above attempts to expose the side of one of the drainfield trenches to make sure conditions in the drainfield appear normal. This includes the thickness and color of the biomat, and the texture of the soil directly beneath the drainfield.
It is my opinion that unless the drainfield is failed with sewage on the ground (SOG), or at least one of the three tests above are performed, a saturated condition can not be definitively diagnosed. Others may disagree.
Subject: My Dog Smells Like Sewage!
Posted: Bernie March 27, 2004
Hello, We had a septic system installed 3 years ago and have not seen any problems up until now. About a week ago, our dog came to the door smelling like sewage so when we went to investigate, we found, in our front yard (where the septic tank is) a circle of toilet paper around a pipe (I believe it is for clean-out or something). The cap for the pipe was in place but the top of the pipe is cracked (I believe from a lawnmower) so water and toilet paper was able to get out. There is another "pipe" closer to the house that does not have anything coming up out of and nothing is backing up in our house.
From doing some searching, I came across information that speaks about high water levels in early spring (now) but I'm not sure exactly how that relates to our problem specifically or how we can deal with this problem. Our tank is concrete and, though it slopes down to our raised filter bed, a pump is installed (regulations?). We have a 4200 sq. ft home with 3 full baths and one half bath but have only my wife, my step-daughter and myself living there. I don't believe we use an abnormal amount of water in our home either.
One concern that I do have is the disposal of tampons into the septic system and the effects that may have. Do you have any ideas as to what could be causing this water to rise (and bring with it toilet paper, etc.) and what we can do about it. Bernie
Along with returning birds, sunshine and nice weather, spring brings out septic problems. Along with my tulips and regular spring rush of building projects, I have several dozen questions like yours. People with problems should understand that the letters published here are the best of the many that I receive. I try to answer all questions, but I offer no guarantees.
With normal use, and a three year old system, your problem is more likely a plumbing type of problem. Why not have the tank pumped and checked? It may be a blockage in the sewer line before the tank, caused by slope problems in the sewer line, or a similar plumbing problem. You may want to call in a designer or excavator to check slope conditions within the system with a laser level. Local health would have the name of the original designer on file, as well as the original septic system plans. As a professional designer myself, I would want to know about any problem in a newer system I had designed.
Disposal of tampons in a septic system is not a good idea. See also this question.
Subject: Is a Quick Fix Possible for a Slow Drainfield?
Posted: Dave and Bonnie, Pierce County, WA March 27, 2004
We have a pressurized system in Pierce County, WA. The tank is in the back/side yard and the drainfield is in the front. The problem is that under high rains (and under heavy use), we get septic rising to the surface and making quite the stink!
The house is 7 years old and we have had this problem off and on for the last 4 years. We had the tank pumped (and one of the baffles fixed) last year. Also, the septic company suggested fracturing the soil to try and break the hardpan (injecting air and polystyrene beads into the soil to increase capacity). All that accomplished was giving the front lawn high and low spots.
We have the plans and the one thing that stands out to me is the lines show a maximum depth of 6-9". I have never heard of such a shallow depth. Can you give me any feedback?
Dave and Bonnie, A shallow drainfield is good when soil depth is shallow. Sounds like poor soil as well. In these cases, the system must be put in the ground as shallow as possible to utilize all of the available soil under the drainfield for treatment.
Under these circumstances, what is a possible solution?
Without seeing your property, it is not a good idea for me to diagnose your specific problem, and the general problem is well covered on the website. However, your description is of a failed drainfield. The soil treatment method you attempted has a mixed success rate, and your experience is typical of many letters I get. The certain solution is replacing the drainfield in another location, but a definitive diagnosis by a respected local designer is your best approach. I always advise retaining and preserving the old drainfield for future use as a backup.
Subject: Frozen Septic Caused by Check Valve? I want to get rid of this Valve
Posted: Mike, Wisconsin January 9, 2004
Hi, Your site is a real find. Thank-you for being there.
I have had an effluent pump failure and am in the process of tracking down a new pump. I am leaning towards getting a certain pump from a local company that is one of their 'High Head' models as we have a fairly good distance to the drainage field.
Some background: The old set-up had a check valve in it (which may have caused the pump failure as I believe a bit of water in the pipe froze in the valve....). I have read various parts of your site where you have explained nicely why you don't want/need a check valve. The fellow I had come out and trouble shoot the system indicated that there should not be a check valve there so we will not replace the check valve when we install the new pump.
My question is this: Would it make any sense to install a effluent filter at this point? How do the effluent filters deal with the back flow? How do they deal with cold weather? Is the current thinking about a weep hole the same (Not a good idea?) How would you design the connection with and without a filter?
Mike
Mike, The effluent filter (reusable cartridge type) now goes in the septic tank on the outlet side, and will not affect the pump chamber or discharge line, and is a good idea. I know of no filter kit for the discharge side of a septic effluent pump.
To remove the check valve may or may not be OK depending on the design of the system. The freezing in the system that you experienced may not have occurred in the check valve as you speculated, and the check valve may be in the system for another reason altogether. For instance, if the drainfield was not designed for "drainback pressures", when the pump shuts off it may suck goo from the bottom of the drainfield into the lateral pipe system. If on your site, the drainfield is higher in elevation than the invert of the pump chamber, then the lateral lines must be suspended from the drainfield vaults or set on concrete blocks (if vaults are used in the system) and the laterals must not be lying on the floor of the trench. If in your system, any drainfield lateral is lower than the high water level in the pump chamber, then the highest point in the transport line will need a check valve open to the air to prevent the pump chamber from being siphoned dry when the pump shuts off. This is a possible second reason for the weep hole in the discharge line, a vacuum break.
I recommend you get a copy of the original plans from local health and study them before making changes. Remember, the pump you put in must match the one you removed, both in gallons per minute, and total dynamic head. Make sure you get advice on this from a qualified person, ideally the one who designed the system in the first place.
Subject: A Costly Repair to a Cheap Septic System
Posted: Candy, Arkansas October 3, 2003
This spring we moved into a beautiful home by the lake. Last week our septic system alarm went off and we had water around the lid in the yard. The local septic guy came out and said the screen had collapsed over the pump and the screen, the pump and the floats were ruined and had to be replaced. The electrical panel was not up to code, even though the former owners told us they had the system completely replaced a few years ago with the latest type of pressurized system. The whole thing cost us over two thousand dollars including trenching out to the septic system from the panel in the garage and replacing several pipes in the lawn sprinklers in the process. The septic guy said that the drainfield may need replacing due to a wet spot in the lawn for an additional three or four thousand. He did a little digging with an auger, but said he could not tell exactly where the drainfield was to assess its condition.
The question is this: If we have to replace the system, how do we know if the new system is a good quality system or a cheap system that will cause us further headaches?
Candy, I get many questions such as yours, so based on your experience, here is an article to help you tell if your system is a good one or a clunker:
Do You Own a Good, Bad or Ugly System? & How to Tell
A cheap pressure system can be built without a reusable cartridge type filter (an additional $50 or so). Cartridge filters are much easier to maintain than the older and cheaper screened vault surrounding the pump. The screened vault is impossible to clean and hard to remove, especially if the screen collapses around the pump due to lack of maintenance. The cartridge lives under a green lid and has a "t" handle. It is simply pulled up and hosed off into the tank once or twice a year as needed.
A control panel with a disconnect breaker, is an extra $60 over a simple alarm box. The panel is usually required by electrical laws in most places within 50 feet and in sight of the pump chamber. Septic systems are often skipped over by the electrical inspectors. Some installers get away with putting in the alarm box instead of the panel, pocketing the $60.
An elapsed time counter (a $30 item, but only if a control panel is already part of the system) tells the home owner how long the pump has been running total. With this item, you can calculate how many gallons of sewage the pump has moved to the drainfield on any given day, week, month or year. This information is critical to diagnose a failed system, and can be used to prevent overload by a careful homeowner. Because every septic system is designed to handle a specific daily volume of sewage, checking the number from time to time, particularly after a busy weekend is the best way to prevent continual overloads that can kill any system. The counter is like a car odometer and can not be reset.
Ports are 4 inch diameter plastic tubes with a threaded cap and set level with the lawn. They penetrate the ground and reach to the bottom of the drainfield. By dipping a stick down to the bottom of the drainfield, the owner can find out how much liquid is sitting in the bottom of the drainfield waiting to soak into the ground. An inch or two or less liquid in the bottom of the port is normal on regular days. Chronic higher levels in the ports mean trouble will show up soon.
Without these four items, the excavator can put a couple of hundred bucks in his or her pocket. Most of the customers will not know the difference. However, the homeowner will have a lesser system. Insist on these four items when you discuss the system with your designer. Make sure you get the items by telling the excavator that you will look for them when the system is turned over to you at time of final inspection. They can not be added later without difficulty. Also, your system needs to provide access to the pump chamber and the septic tank with risers (access tubes from the tanks up to the surface). You should see at least two green 24" diameter slip resistant fiberglass lids in your yard with stainless, tamper resistant flush mounted bolts (usually allen bolts). Three lids are even better to access the system without digging up the yard. One lid only and none of the four items mentioned above means that you have purchased the cheapest legal system. Excavators may try to convince you that these items are "bells" and "whistles". However, you may never see the excavator again once the system is in, and you will have to live with your system every day. Trouble usually comes on a dark and stormy night, and usually with a table full of guests, announced by the cry "MOMMY! The toilet wont flush!"
Subject: I Want to Change the Shape of my Mound
Posted: Ned & Pam, Minnesota October 1, 2003
We live in Minnesota, on a 2/3 acre lot with a well in the front. Our septic system is 34 years old and is failing. Soil samples indicate that a mound system will be required for the replacement system. The placement of the mound on our sloping yard suggests to me that a retaining wall along the closest edge of the field, which is 9' from the short end of the rock field, would be a nice way to landscape. This would add some extra soil above the sand but would not disturb the mound field. Does this sound feasible? Ned & Pam
Ned & Pam, This should not be a problem to reduce the mound from the "high side" as long as the mound is oriented as it should be - across the hydraulic gradient - the direction of sub surface drainage (not necessarily in the same direction as surface drainage) - the length of the mound must cross the subsurface slope, and footings for a retaining wall would only interfere with drainage down-slope of the discharge - run it by the designer - also consider an above ground bottomless sand filter design if allowed, which in practical terms is a mound system without the side slopes - above ground sand filters take up less space, can be disguised as raised planting beds, and used as garden spaces as well. A sand filter with the addition of an air pump, should perform better than the mound.
Subject: Covering Part of the Drainfield
Posted: John October 1, 2003
We are putting in a pool. But we will need to partially cover approximately 20 feet of one lateral line. Will this hurt the lateral lines. John
John, In spite of the pool, you must preserve space for a replacement area - why not see if you have enough space in the yard with the pool and the septic system and the replacement area and an added line to replace the one under the pool deck - if so, I would not have a problem covering part of the system, because you have the space to replace if something goes wrong. Use interlocking blocks instead of solid concrete over the line. Solid paving and car traffic are the things to avoid over a drainfield or replacement area.
Subject: Adding An RV to My Septic System
Posted: William August 2, 2003
Can we tie our travel trailer into our residential septic tank?
It is customary for a few days - if you want to make the addition permanent, base it on the number of bedrooms in your home - do not put more people on the system than twice the number of bedrooms in the home. For example, if you have a 3 bedroom home, put no more than 6 people on the system permanently, regardless of if they are in the travel trailer or in the home, and regardless of the number of bathrooms in the home.
Adding an RV to a home will work only if the septic system is correctly designed for the number of bedrooms in the home. If you do not know if the system is correctly designed, check your record of the system at county health. Ask them specifically how many bedrooms your system is designed to handle. If your home has had extra bedrooms added some time after the original construction, in the basement, or attic - the system may or may not have been pre-designed or enlarged to accommodate these extra people. This is one of the ways unexpected failure of the septic system can occur.
Subject: My Septic System's Warning Buzzer Went Off
Posted: Ron August 2, 2003
We have a pressurized system and had our 2 section tank cleaned recently and everything seemed normal. From the tank, the sewage travels about 30 feet and up hill about 3 feet to a flat 15 x 40 foot drain rocked area which is the drain bed about a foot deep. My tank warning buzzer has gone off a couple times in the last couple weeks. A couple years ago we have had some trouble with the drain field bubbling above ground so we had it back-flushed to remove sludge from the system's PVC piping. I am speculating that the bed cannot hold the volume of sewage when the pump turns on, and is draining back down the main line and into the tank. Is this a plausible theory or is it more likely a tank/pump problem? In the mean time, I am thinking about back-flushing the system again.
Your theory could be correct - the bed should accept the volume of sewage if it is operating normally - check ports in bed if you have them for excessive levels. This is the proof that the drainfield has failed.
The warning buzzer is triggered by the top float in the pump chamber that trips when the pump is not doing its job for some reason. This can happen when the pump is worn out, or when the drainfield can not take the effluent that the pump is sending to the drainfield. In some cases, the backflow from a troubled drainfield causes the pump to continually cycle in a futile attempt to clear the pump chamber until the high level alarm sounds. Any alarm should be diagnosed right away to prevent worse problems.
The system is basically a rectangle of drain rock that has 3 fingers of PVC pipe running thru it, that distributes the volume of sewage in the pump cycle. No ports that I know of, but I will back-flush the system. If the bed is overused and approaching it's limit of usefulness, do you think it would be feasible, or even make sense, to add any extensions of perforated PVC pipe to increase the area to which the system pumps to? I am thinking this would be a temporary fix but hopefully it would delay relocating the drain field. Maybe it would take enough pressure off the main bed to help it recover and work properly.
Ron, I think you are a little over your depth to repair this pressurized system without expert advice. You need to consult with someone familiar with your area and who has seen your site.
Good thought, thanks. I was temporarily on the dark side of the moon, but with you brought me back. I will have it back-flushed by an expert and ask for an assessment.
A final thought - the term "back flushing" relates more to water softeners and pool filters, than septic systems - you are probably referring to the flushing and "sweeping" of the inside of the distribution laterals in the drainfield with fresh water and a bottle brush duct taped to a flexible half-inch polyethylene pipe. If your system has been designed with this important maintenance job in mind (and some are not), it will help the distribution of effluent in the drainfield, if done every ten years or so. The laterals (the 1 inch diameter PVC pipes with one-eighth inch diameter holes or orifices along their length, that spread the effluent under pressure into the drainfield) tend to clog up with sludge over the years. The message below explains the cleaning method quite well. In your case, you had this done a couple of years ago. Not enough time has passed to justify having this done again, and little benefit will result. When effluent begins to flood the drainfield, distribution is not the problem, but soil saturation is.
Subject: My Neighbor Messed-Up My Septic Drainage
Posted: Laura June 15, 2003
Our septic system was updated 5 years ago. Last year a neighboring property owner placed a large amount of soil at the end of the field where our septic drain bed is located. (Area is quite a distance from the drain bed). The soil deposit caused a drainage problem on our property. Until recently, we believed the problem was strictly from the dirt mound. (Our property drains naturally north over the other owners land.) Now, we are being told that the neighbor broke a drainage tile on his property at the time he dredged and then filled the area. He now says he broke the tile and then filled it. He says this tile breakage is really the reason we are now having drainage problems. He now says he believes this tile runs 3 to 4 feet below our septic drainage field. Help! What are your thoughts? Laura
Without viewing the site , I can only provide speculation, so you need an opinion from a local designer of septic systems to look at your property. However, it sounds like your neighbor may have a French drain, or should I say Freedom drain on his property. It is possible that this drain keeps some of your drainfield from saturating. If your drainfield depends on extra groundwater drainage, this drainage should be built on your property, not on your neighbors. Your septic system can not depend on drainage systems on other property unless there is a perpetual drainage easement on your neighbor's title explaining the extent and details of this drainage. If your neighbor was excavating on your property, then he should fix the drainage and remove the dirt.
Subject: My Tank Plugs Up Regularly
Posted: Robin June 15, 2003
My system has two tanks 1000gal. The problem I am having is in the first tank from the house. The paper builds up at the end of the pipe. Every so often I need to open the top and move the paper or water will back up into the house. My system is 13 years old. I have it pumped every other year. There is only my wife and I living here. Every time I have it pumped out I ask the person what may be the problem. I never get an answer. Robin
Perhaps the slope of the sewer pipe at the end of the run near the tank has insufficient slope to move things along. I would check the elevation of the pipe in two places. One at the tank inlet, and the other at the foundation wall where it leaves the house. You will need a survey instrument to do this with an accuracy of better than a quarter of an inch. The slope of your sewer should be between 1 inch every 4 feet of pipe to 1 inch every 8 feet of pipe. In other words, if the sewer line to the tank is 32 feet long, it should fall between 4 and 8 inches end to end. You really should check the pipe in the middle also to make sure that the first part of the pipe slope is consistent with that near the tank at the end, specially if the second tank was added to the system at some time in the past - hope this helps
P.S. Why two 1000 gal tanks? This extra tank may have been added for some specific and unknown reason and reduced the drainage slope for the system.
Subject: My Drainfield Is Getting Old
Posted: Jan, Massachusetts May 8, 2003
Hi, I found your web site extremely informative, describing and evaluating different types of septic systems without bias towards any of them. One subject was not mentioned however: septic system repairs or replacements. My interest in septic systems is forced by real need and not love to the subject, although very interesting. I have owned my 3 bedroom house for 20 years; house is 38 years old. Septic system consists of separate septic tank and huge, deep, bottomless, concrete perforated pit. System is working "OK" without overflowing, with two of us living here, but pit is full up to half of the riser (1 foot below the ground level) when kids are visiting for two weeks or so. Lot is 1/3 of an acre, front yard with septic system is 55' x 35'. Any suggestions? Sincerely, Jan
thanks for the compliment - you seem to have a cess-pool (dry-well) type septic system - you seem also to be up on the topic more than most home-owners - I suggest you find the best installer in the area and get a price on a replacement - plan to keep the current dry-well and you will probably never need to make another drainfield repair - look into the use of the bull run valve to switch back and forth between the old and new drainfields when you have a heavy week - i.e. keep the old drainfield as a backup - after a year or so without use, a drainfield or dry-well will usually recover completely to its original capacity
Thank you for your advice. I guess, I have to do it sooner rather than latter. Once more, Good job with your web site. Sincerely, Jan.
No, thanks for yours - you are right, the site does not cover many repairs to conventional systems - I will post this message for people with repairs in mind
Subject: Results of Another Sand Filter Failure
Posted: Blaine March 31, 2003
Hello. I am the proud new owner of a sand filter system. In contacting a septic service to view this system, was told to toss it and put in a packaged treatment system, this would be over 5 grand or more. Ok, now for some spec's, the whole system is about 6 years old, has a 2 chamber main tank with screen, a pump tank (new pump), a sand filter with a new pump, and a mound. Everything is fine with the main tank, pump tank, and the mound, this from the septic service. Now for the sand filter, the top two and a half feet of material was removed by the last owner, they had over loaded the system, the plastic pipes are exposed, the liner is in good shape but the septic service says the sand and gravel have mixed and this was due to a hydraulic over-loading of the system. Because of the sand and gravel mixing it would be better to toss the whole thing ? Would like your opinion. Thanks Blaine
Blaine, Six years seems too soon for a rebuild of the system - sand and gravel generally do not mix due to hydraulic loading if layered according to standard practice - most installers do not know this - is the gravel "pea gravel" or "drainrock"? - I say watch your water use and wait till the thing fails - you still do not know why the thing failed in the first place - for instance how was the system "overloaded" to cause the failure - does the system have an "elapsed time counter?" - if it does, if you do not exceed the design load, it may continue working for a long time - let me know
Thanks for the Information. Now to give some more details. I have learned the system was designed for 4 bedrooms. The last people that lived there had seven people, two adults and five children on the system. The material used was a small rock, like five-eights crushed minus, then the sand layer. The sand filter has been open to the atmosphere for about four months I learned, so at least it got some oxygen. It don't have an "elapsed time counter" . Yesterday I opened the two ends of the pipes that are on the mound, started the sand filter pump and flushed them out, nothing but water came out, took a stiff bottle brush, one that fit right, connected sixty feet of plastic conduct and brush it out, got just a very little bit of algae, flushed it again, installed threaded caps. One last thing, there is a vegetation mat starting to grow in the sand filter. I assume that I will have to remove this and add material on top of the exposed pipes. What do I put on top of the pipes? The distance from surface to pipes is about two and half feet. Thanks again. Blaine
The large family was likely pushing the design limit of the sand filter even if it was designed correctly, depending only on their habits of water use. Leaving the filter open to the air is OK, even good, except that the 2.5 foot drop to the filter surface will be a problem. You will have to add dirt to level, but this will restrict aeration a little. You might add pea gravel to grade to allow some air into the filter and arrange a few potted plants for decoration. Grass is the usual cover though. I would remove vegetation and put a little pea gravel over the pipes and rake it flat. Place filter fabric over the pea gravel before backfilling with loam or gravel.
Your account of cleaning the lateral lines is very good and should be of interest to all readers who own a pressurized system, mounds, trench systems etc. This maintenance and check with flush and brush of each lateral line should be performed every ten years or sooner depending on use. Some sludge usually piles up at the ends of the laterals over time. Besides cleaning the effluent filter and checking things for deterioration, it is the only real maintenance required on pressurized systems. If you have a mound following the sand filter, the mound will not have sludge in the lines because the sand filter eliminates solids in the discharge (but not bacteria). The lateral lines in the sand filter require this attention to preserve even distribution of the effluent, and complete use of all of the filter surface.
I strongly recommend the addition of an elapsed time counter, particularly on a sand filter. This design is effective but very sensitive to overload, and locks up suddenly when overstressed. An elapsed time counter on the pump circuit gives run time in hours and can tell you exactly when your system exceeds design specs.
Subject: Addition Built On Top of Septic Tank
Posted: Sandy February 12, 2003
I bought a home from a local person and later found out he built a large kitchen addition over an active septic tank - my family and I did notice a strong odor entering the interior of our house occasionally - we would have to air our house out by opening doors and windows. We have four children ranging in age 16 months to 15. Could you let us know the dangers of having a septic tank under the house are and what the odor may be? Thank you. Sandy
Sandy, Even though the tank may be under the floor, it should not give off an odor. If the addition was built over the tank, there may be other problems associated with construction of the system that require attention. Six people in the home including young children gives a septic system a workout and everything in the system must be in good shape. It is unlikely that local health or the building department inspected the kitchen addition and missed the tank, although I have heard of such things. Generally tanks must be at least 5 feet from building footings outside the walls of the house. The drainfield is usually at least 10 feet from a footing.
You need to have a licensed installer or designer investigate your system for a fix and to check on your local set-back rules. Local health may allow you to abandon the tank "in place" by pumping it out and filling it with sand. I have seen this done relatively inexpensively, as long as you have decent clearance in the crawl space to work. In the best case, a new tank will fit in the yard and existing piping can be re-routed through this new tank without disturbing anything else.
Subject: Solar Septic System?
Posted: Shairn and Victor January 10, 2003
I have two questions.
One, is: if we use composting toilets,
is there any way to simplify our septic design since it is just handling greywater?
Two: are there solar pressure pumps available for pressurized drainfields?
Shairn and Victor
Shairn and Victor, State and local laws determine if you are entitled to a reduction in drainfield area by removing blackwater to a sealed treatment device, or even if such devices are legal in your county or parish. However, now that toilets have been engineered to use less than 2 gallons per flush (older toilets used to use up to 5 gallons) don't expect a big break.
Toilets in the average home now probably use fifteen percent or less of the water used in the home. An intermittent siphon made of plastic, for a few hundred dollars, can be used to periodically dose a pressurized drainfield without the use of electricity from any source. A siphon system can be designed to power a mound or sand filter, but only where the septic tank is higher than the drainfield by at least 5 feet.
I know of no "active solar powered" septic system. However, if you attached standard solar panels and batteries to the small pump that customarily moves fluids around in the septic system, it would be a solar septic system. Gravity type septic systems use falling water to function, technically a solar pressure pump.
Remember though, grey water is not harmless, and can contain the same pathogens (germs) found in septic tanks. It is a myth that greywater is safe and can be safely sprayed on landscaping plants. Check your local laws.Your designer must meet all local regulations and solve the sewage disposal problem too. To get a siphon type septic system design, expect to pay more than the regular design fee is in your area for a regular septic system. However, you should pay less for the construction of the final system (over a standard pressure system) because you avoid running power to the tank, plus you do not have to buy a pump and control panel. Besides, you will pay zero for power over the life cycle of the system, although the "good" bacteria in the drainfield will work just as hard.
Subject: Septic Tank Leaks Into Basement Through Drain Hole
Posted: Correll December 30, 2002
This past weekend my basement began flooding with sewerage water. The amount of sewerage water that was coming up through the seams of the slab floor perimeter led me to believe that the septic tank had cracked somewhere on the bottom of the tank. When the septic company arrived and removed the manhole cover, sure enough the tank was almost empty. Given that the tank and house are only 6 six years old (at least that is when the tank was installed) the septic guy didn't think that the tank was cracked. Rather, he thought that the small drain hole, about the size of a quarter, at the bottom of the tank, was open. Sure enough, it was. Apparently, this drain hole is for draining rain water while the tanks are curing. They are supposed to be plugged with what looks like a rubber cork. He pumped the tank dry, climbed down into the tank, pounded in a new rubber cork brought in by his boss (who has been the business for the last 30 years) and covered the whole area with hydraulic cement to make sure it didn't happen again. The septic guy seemed to think that the hole had never been plugged, although, when I had the tank pumped about 18 months ago, the tank was full. I said this but he said that it can take a while, depending on conditions. He relayed a story about a local whose tank did something similar after 20 years. Do you know anything about these plugs? I have tried to search the internet but cannot find any information about them. Correll
Correll, It sounds like the pumper may have sucked up the plug during service. The idea of providing a drain plug in a tank that is supposed not to leak, is an odd idea, regardless of any reason. I can not think that the amount of rainwater that could fall into a manhole over the 8 to 10 days required to cure a concrete tank would ever justify the provision of a "drain hole" except perhaps in Noah's county, after the flood.
Subject: What Size Septic Tank do we need?
Posted: Michelle & Steve December 26, 2002
My husband & I are in the middle of attempting to put on an addition adding one bedroom to a 2-bedroom home. We do currently have a 1000 gal tank & the Board of Health Dept is making us go through a list of things to get their approval before construction can begin. They are indicating that it may be essential to upgrade the septic from 1000 gal to 1500. Is this really necessary? We certainly can't afford the cost of a whole new system. Please let us know your thoughts! Michelle & Steve
Michelle & Steve, In some counties, a 1000 gallon tank is plenty for three bedrooms. The state regulations usually dictate the size a septic tank must be, and county regulations can be more strict, but not less. The rule of thumb for tank size is one-and-a-half times the daily design flow. Therefore, if the design flow is 360 gallons per day for a 3 bedroom house (120 gal/bedroom x 1.5) = 540 gallons tank size. However, anymore this sizing formula has been abandoned for single family homes and is used only for apartment buildings and larger systems where regular maintenance is more certain.
For single family homes, a more arbitrary standard has been adopted in many states and counties. This standard includes much larger sized tanks based on the notion that people put off having their tanks pumped.
For single family homes, three tank sizes are commonly built due to somewhat universal concrete forms. They are 1000 gal, 1250 gal and 1500 gal. Generally, the 1000 gal tank size is considered ample for two and three bedroom homes with 1250 gal for four bedrooms and 1500 for 5 bedrooms. Additional bedrooms require 250 additional gallons each.
My State, Washington, for some reason is more liberal and allows 4 bedrooms on a 1000 gal tank with 250 gallons for each bedroom thereafter. Washington, however requires two compartment tanks.
I am afraid that your county has the authority to require as big a tank as it wants, with not much for an individual to say. Counties attempt to be hard line about such things as long as everyone goes along with it. If you point out that their standards are too strict, everyone who has had to bite the bullet on an arbitrary rule will be upset with you, and the county probably already has its heels dug in deep anyway.
As a strategy, you might try to convince the health department that the new bedroom is actually an office by showing no door, or no closet in the plans (check with the building department to get their standards for identifying a bedroom). If you do not have more than 4 regular occupants in the home (2 people per bedroom) and your system is properly sized for the 2 existing bedrooms, then you should not have problems with the system. Click here to see that you have enough drainfield for your two bedrooms (a more important concern than tank size). The addition of an office, or even a bathroom in a home should not require any changes to the septic system, because you are not adding any bedrooms (people living in the home). Let me know how it goes.
Subject: Another Freezing Sewer Line Question - Use of Check Valve Questioned
Posted: Ian, Northern Ontario November 14, 2002
I have been reading your forum and found the articles very informative. We have a cottage in northern Ontario that has a septic tank. Recently we have replaced the entire tank and now have a 36" pump chamber with a Sewage pump that pumps the raw sewage to the septic tank 180ft away (approx 20ft. of rise.) I know that we have a check valve in the pump chamber. The sewage line going to the tank is buried between 6" and 3ft. insulated with Tundra 1/2" wrap. The chamber is buried only about 6" below the surface. Finally the question..... What do I need to do to winterize this system so that I can leave it for 3-4 months and is there any way of heating the line up to the tank to insure no chance of freezing if I do want to use it in the winter. Thanks in advance, Ian
Ian, The best way to prevent freezing of a sewer line is to drain the line when not in use by having lines automatically drain back when pumps shut off. I have designed hundreds of systems that drain back this way and have never had a call back. See this letter for more on this issue.
It sounds like your system uses a Grinder Pump, which can not drain back because it pumps solids. The best design for a grinder, is to place the pump inside the house in the floor in a small pump vault. The discharge line, septic tank and large pump chamber can be buried outside, deep in the ground beyond the reach of frost. Then the effluent line can drain back into the large pump chamber through the pump.
A deep buried system, with multiple tanks close to the house, may be hard to get to with a pump truck for maintenance. Also, I suspect you may have a gravity system. Your grinder pump is only needed to get the sewage up to the remote septic tank. In this case, clear the pump chamber of solids by flushing with clear water. Fill the pump chamber with a low impact RV anti-freeze solution of the right mix to withstand your worst case freeze. Next, run the pump until the anti-freeze fills the discharge line all the way to the septic tank (open the tank and watch for the change of color). Make sure no fresh water will run into the pump system from dripping taps in the house, etc., or it will freshen the anti-freeze in the discharge line. However, don't de-energize the pump for the winter, unless the water system is completely drained. A frozen line is easier to deal with than a flooded house. In the spring, fire up the system and use normally. Don't worry about the anti-freeze hurting the bacteria.
Incidentally, to determine your anti-freeze mixture, 100 Ft. of Sch-40 discharge line will contain the following volumes:
1" diameter 4.5 gal., 1.25" diameter = 7.8 gal., 1.5" diameter 10.5 gal., 2" diameter 17.5 gal.
Instead of anti-freeze, if you want to use the system periodically during the winter, do not use heat tape on plastic pipe. I would design a drain for the sewage line downhill from the pump chamber. Flush the pump chamber into the septic system with clear water, and then bypass the check valve and discharge the line downhill into a small gravel drain designed for the purpose. The whole thing could be hidden underground.
Subject: Shoddy Septic Design - Sand Filter Required
Posted: Linda, New York November 10, 2002
Thank you . your site is very
helpful.
I have to redo my existing septic system and ideas have been thrown out - like
aeration system pumping station or -re-plumb the house , move
the tank and install sand filter. I just had a new tank installed 4
years ago and now the inspector is saying I cannot use it because it is not a
two chamber-- that law was passed in 1991 and this tank installed in 1997. Thank
you for ANY help or ideas to explain this stuff. Linda
A lot of unclear items. If you had a tank installed 4 years ago, the inspector should have caught the issue about the number of chambers. Was the tank inspected by county health at that time? If not why not? Whoever is "throwing out ideas" is confusing the issue and not helping. If the person throwing out ideas is not qualified to design, repair or inspect systems, ignore their advice. Is the new tank in use now, or was it not put in service? Why do you have to "redo" the septic system? If the new tank came from a legal source, they should have known about the two chamber thing. What state are you in. Many states allow a one chamber tank system. However, if your state requires two chamber systems, you may be compelled to make this change. If the lack of a two chamber system was recently noticed by an inspector yet the tank was placed 4 years ago, why did this issue come up after 4 years?
You are so right. Four years ago the
contractor was replacing the existing tank and was permitted to use a one
chamber tank and grandfather to the existing piping ( which I have since
discovered is a direct run off - no field attached) and so -- they -- "got away
with" a one chamber tank. Where this tank sits is the real problem. It is too
low to allow for a sand filter or any type of field. Even if I went with an
aeration system. I would need a dual chamber tank or at least an additional tank
and pumping system. - I am in NY - that is equal expense and additional electric
and maintenance costs. Sooooo it looks like my best option is to re-rout the
plumbing to cross the cellar to the outer wall, run the length of the house out
doors to the front yard then join the new tank and sand filter system . Still
$5000 - 6000 but the neighbor who chose the aeration said his cost $6000 ( Our
houses are similar in design and levels - yards. ) So now, what kind of failure
rate do sand filters , professionally installed, have? The neighbor tells me
horror stories of his sister's mound sand filter. I know that there are many
variables, and no answer you give me is an absolute. I am going with the sand
filter design - I am just trying to know what to anticipate in the future.
Thank you so very much for your help and advice.
Linda
Linda, If you have to change to an alternative system (pressurized pumping type system), you will have to add a pump chamber anyway. The best way to do this is to add a 1000 gal, two compartment septic tank and use the smaller chamber as the second chamber of the system and the larger chamber as a pump tank. In other words the second tank is placed backwards. This makes the pumping chamber larger which gives a little more emergency storage as well as allowing a smaller dose height within the pump chamber which makes calculating the system a little more flexible. This should be acceptable to local health and reflects what should have probably been required first time around (a pressurized system), particularly if your close neighbor has an aeration system.
The sand filter system would be my choice at this time over a packaged aerobic unit. The sand filter is a good and reliable system if installed by an experienced excavator using the best quality clean sand (coarser better than finer using the ASTM C-33 specification) and high quality components. Frequent small doses are better than larger ones, orifice size no greater than 1/8", orifice spacing and lateral spacing within the filter should not exceed one-and-a-half feet (look for at least 33 orifices per bedroom regardless of any other factors), and include an air coil within the filter (you may need to increase aeration in a pinch). Failure rates are higher with mounds and sand filters than with conventional pressure systems, likely because these systems have more parts, not because of flaws in the technology. If you do the above, your potential failure rate will be well within conventional alternative designs.
I recommend you read over the material on this page concerning sand filter sand and sand filter failure and packaged systems. P.S. your inquiry exhibits a lot of patience considering the complexity and questionable advice and work you have had to deal with and pay for.
Subject: He Pumped the Wrong Tank, and Charged Me!
Posted: Bummed, Oregon October 28, 2002
Here's my
problem. After inheriting my Father's home due to his sudden death, I was
advised to have the septic tank pumped by a plumber. (I had the plumber get the
tree roots out of the line.) He located the tank for me, but when I tried to
locate, and dig it a few weeks later, could not find it.
I then called a septic specialist(?!) to locate, dig and pump it out. He did
this, after telling me that the plumber had not located the tank, it was in a
different spot. He then proceeded to pump the tank he located. WELL, it was the
old tank, no longer in use for at least thirty years! The newer tank was where
we had told him we tried to locate it! Now we are in a dispute over this. I
believe he should pump the one in use free of charge. He says he owes us
nothing. What the heck can I do? Isn't there a way to tell the difference
between an old tank, and one that is in use??
I am so upset over this. I would appreciate any help or advice in the matter.
Thanks so much. "Bummed Out" in Oregon
Bummed, The fact that you discovered an abandoned tank is good news. Consider yourself lucky to have found it without an accident. Abandoned septic tanks cause serious accidents when they eventually crumble, sometimes with only the weight of a child.
The way to abandon a septic tank following pumping, is to break in the top of the tank with a backhoe, and fill the tank with dirt. I recommend that this be done with all abandoned tanks, although local health may have a slightly different procedure. Your abandoned tank has already been pumped, you are not out any money here.
To determine which tank is active, and which one has been abandoned, just check the tanks after a few days. The empty one would be the abandoned one. If neither is empty after a few days, start looking for the building that drains into the tank. Make sure that you do not have two tanks coming from one building. Different colors of tracing dye (an inexpensive item) may be flushed from the various toilets to confirm suspicions. Local health can suggest a source, sell you some, or even give you some powdered or liquid dye in a baggie or bottle.
Subject: Relocating A Drainfield
Posted: Roy, Washington State Pacific Coast October 10, 2002
I am wondering if it is possible to relocate drainfields? We have property with a drainfield from another lot going through it that limits the building envelope and we'd like to increase this.... do you know where I'd start to research this question? Thanks for your help. Roy
Roy, What you are proposing is known as an "alteration". The main issue to consider is space and setbacks from water lines, buildings and driveways. Usually not a difficult job, depending on space. You either can or can not do what you want depending on the county rules. Hire a good designer to find out and then you will know. There are several space saving alternatives available in the world of septic design for a price if you wind up in a jam. Incidentally, you should not have a septic drainfield from another lot going through yours. Go to your county health department and pull the files for the offending drainfields and find out when, if and how the drainfields were approved on your property. If no permits were granted, then you have a simpler issue of adverse possession to resolve with the owners. Your solution may be allowed to use creative interpretation of the county health rules if the county was somewhat hasty in approving the encroaching drainfields.
Subject: I Don't Want a Frozen Sewer
Posted: John Colorado September 29, 2002
The Think Tank is a great site, thank you. I keep coming back to it. I'm installing a PVC waste line from the back of my house to my septic. Sloping at 1/4" per foot, the line rises out of the ground as it reaches the house. Your site mentioned that if the slope is correct, I should not have problems with freezing. I live in a harsh mountain environment in Colorado and am worried about it. Should I insulate this pipe or will it be OK? If so, with what? Thanks John
John, Thanks for a timely question. As winter approaches I get questions about freezing pipes etc., and lately I am getting plumbing questions.
If you are going to be away from the home for extended periods, then no water will flow, and no freezing could happen. If on the other hand, if you are there all the time, with warm waste water flowing several times during the day, then the pipe will never freeze. This is due to warm water pushing the freezing front back beyond the area of the sewer. Therefore, the only problem with freezing will happen due to an unexpected trickle of cold water that could freeze and pile up in the pipe. Preventing toilets and taps from doing the slow trickle thing (regular maintenance), is a good protection from freezing sewers (you can check outside the home by looking in the cleanout for a small stream after things are quiet in the home or check at the tank outlet if you have access through a riser and lid - remember, a toilet flush can take 15 - 20 minutes to clear the tank).