Failing Drain Field

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    • #278901

      I was looking up information for drain field problems and came across your bulletin board. I have a question or several if you would be so kind. I have a 15 year old home with a septic system. About 6 months ago i noticed seepage at one spot in the drain field. We had our tank pumped, which i was told had never been done before. It temporarly fixed the problem. Then it started seeping again. I dug up the area around the leak and noticed no clog and in fact it was only about 5′ from the end of that leg of the field. I added about 8′ of pipe to the end, in hopes it would relieve what was seeping out. It again only worked temporarly. Now its seeping again, same place.
      My question is, would it hurt to cap the pipe off in front of that leak, maybe even temporarly, to allow that section to dry out. You told multiple people that their failing was probably caused by the sludge mat not allowing proper drainage. You said you need to switch to the alternate field and aeriate that section to allow the microbes to do their thing. Makes sence, but how do you vent it? I do not have an alternate field and would like to avoid the cost and labor in putting one in since the city might be installing a sewer system sometime in the near future. Is there any way around this? Like capping that leg off short? I would appreciate your help on this matter if at all possible. By the way…we have 4 people in our family and probably go through alot of water.

    • #299537
      John Aldrich1

      chukinnc, a clog in the perforated pipe in your leach field is not the cause of your leach field failure. The clog is occurring over the entire infiltrative surface of the soil below, and on the sidewalls of the field. Capping off, or extending the perforated pipe in your leach field will not solve the problem.

      The septic tank effluent is ponded, and contained in the voids between the pieces of gravel in the field. The effluent will flow in the path of least resistance. If the applied volume of effluent cannot percolate through the clogging mat, which has formed at the gravel/soil interface, it will surface at the point of least resistance. In this case, it is surfacing at the wet spot where you excavated to look for a clogged pipe.

      I think that you have no alternative but to install another leach field, and a diversion valve to solve your immediate problem. The size of the new leach field will be determined by the requirements of the regulatory agency in your area. You may be able to negotiate with the authorities to install a smaller leach field in light of the city’s plan to extend the sewer system in the near future.

      If you decide to install a new leach field, I recommend the use of the plastic chamber material that is available as a gravelless leach field alternative. Advanced Drainage Systems, Inc. (ADS) makes a plastic chamber system called the “Bio-Diffuser”. You can view this product on their website at:

      Simply install 4 inch riser pipes from the top of the chamber units, one on each end of the new leach field. The chambers have a 4 inch knockout formed in the top of each unit.

      Secure the risers to the chambers with the use of 2 couplings and a pipe nipple (a coupling below, a pipe nipple extending through the 4 inch hole, and a coupling on top). Then place the riser pipe into the top coupling with the pipe extending to the surface of the ground.

      To install monitoring and ventilation ports in the existing gravel leach field, excavate the soil at each end of the perforated distribution pipe, and install a standard tee in the pipe. Then install the riser pipe to the ground surface.

      Good luck on your project. JWA

    • #299538
      Ken Zoeller

      Before you add more lateral line find the Distribution box and get all the line recieving fluid. ADD dial-a-flows inneach line to adjust them level. You could shut off the one line that is breaking out. Put a riser on the d-box so you can get to it.

    • #299539
      John Aldrich1

      Chukinnc, what is the design of your leach field? Is it a single bed type leach field with perforated distribution pipes installed over a single layer of gravel? Or is it a trench type leach field with individual separate trenches in which the gravel layer of one trench is not connected with the gravel layers of the other trenches?

      In either case, this system may not contain a D-Box. Many leach field systems do not. It is more than likely that you do not know just exactly how your leach field is laid out, given the poor track record of documentation of septic systems in general. Good luck in trying to locate the exact location of a D-Box if in fact there is one.

      If your leach field consists of separate trenches where the gravel layers are not connected, and if there is indeed a D-Box, and you can find it, then Ken Zoeller’s suggestion is valid as a TEMPORARY solution to the immediate problem that you are experiencing. However, even if the leach field is configured in this way, it is still destined to fail. When it will fail is unknown, and unpredictable, but I assure you that it will fail.

      If your leach field is a bed type design, or the gravel layers are connected in separate trenches then Ken’s suggestion is not a solution to the problem.

      It is my belief, and contention that long term service from a soil absorption system can only be attained with the practice of alternating the application of the effluent flow to half of the leach field area on an annual basis. This practice will allow for the clogging mat that is formed at the gravel/soil interface to become unsaturated in the resting half of the field, and will cause the environmental conditions to change from an anaerobic state to an aerobic state. This change in environments will cause destruction of the biological clogging mat, and will renew the soil porosity to its original condition.

      As you can see, it is difficult to trouble shoot a failing leach field without knowledge of just how it was installed. Let us know what you think of this analysis, and what you plan to do by posting a follow-up message on the Bulletin Board. JWA

    • #299540

      If “chukinnc” is in NC, could he contact me as I am familiar with most NC reg’s and site conditions, IF you need additional advice.


    • #299541

      I am a wastewater designer and have a website at
      Suggest you check the ground level at the point of failure is not lower than the rest of the field.
      If you have to replace the effluent disposal trenches look at Low Pressure Effluent Dosing (LPED) systems -more on that on my website.
      If you have any queries just get in touch.
      Dave Miller

    • #299542
      John Aldrich1

      Hey Chukinnc, please have the courtesy to respond to the questions asked of you. I am sure that there are many others around the world that are experiencing the same problem that you are, and are curious as to your plans. I know that I am curious, and interested in solving your immediate problem for your personal benefit, and for the good of the on-site sewage treatment industry in general. JWA

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