Preventing Septic Malfunctions
Posted: December 24, 2012
Failing septic systems can cause significant water quality problems. (Source: King County, Washington)
Onlot sewage systems typically consist of a treatment tank and a soil absorption area. The treatment tank removes and partially biodegrades solids while the soil under the absorption area absorbs and renovates the liquid effluent from the treatment tank.
Properly designed on-lot sewage systems provide adequate treatment and disposal of liquid household wastes. In spite of the efforts of regulators, and contractors to properly design and size these systems, on-lot systems may malfunction. A malfunctioning on-lot system results in sewage backup in the household, untreated sewage emerging at the land surface and possibly groundwater degradation. Although groundwater degradation is seldom visible, it is important since nearby drinking water wells (including your own) and streams can become contaminated. Assuming your on-lot system was properly designed and sited, malfunctioning of on-lot sewage systems usually occurs for one of four reasons: poor installation, hydraulic overloading, biological overloading or lack of maintenance.
The most common of these is to let construction equipment operate on the absorption surface, the surface where the treatment tank effluent is expected to enter the soil. Heavy equipment should never be permitted to track on the absorption surface during installation or on the absorption area after it is put into service. This equipment can compact the absorption surface, compact the absorption area, or break pipes within the aggregate layer. If seepage beds and the associated piping are not installed level, water will not be distributed uniformly over the absorption area. Finally, if surface runoff water is not diverted away from the absorption area, it may flow onto the absorption area. Remember, the system was designed to absorb the household wastewater not an additional volume of surface water.
On-lot sewage systems also often fail because the soil is not capable of absorbing all of the wastewater delivered to it by the sewage system (Hydraulic Overloading), and the drainfield becomes clogged due to the development of a slime layer or biomat created as a result of persistent wet conditions in the absorption area (Biological Overloading).
When your onlot sewage system begins to give you trouble, it’s time for two things; first have the treatment tank pumped, and second is to find a way, such as a family vacation, that will reduce water usage in the home to zero for a short time. Actually, you should have your septic tank pumped every two to three years regardless of whether your on-lot sewage system is giving you problems or not. This will limit the build-up of solids in the septic tank. When solids get too deep in the septic tank, they can be carried to the absorption area with the septic tank effluent.
Septic tank-soil absorption systems were never intended for a lifetime of use without maintenance. Neglecting to maintain your on-lot sewage system can lead to malfunctions. The most important maintenance issue is having your septic tank pumped every two – three years.
With all the things that can go wrong in your system, you may be wondering what you can do to prevent problems from happening. Fortunately, a number of preventive and corrective measures can be undertaken to ensure that your septic system functions properly. Here are several reminders:
- Take every opportunity to conserve water in the home.
- Do not use, or at least severely curtail, the use of a garbage disposal in the home.
- Do not flush non-biodegradable wastes into the septic system.
- Chemical or biological enzyme additives are not recommended.
- Do not add harsh chemical cleaners to your septic system.
- Do not plant deep-rooted plants or trees over or near the absorption area.
- You can also have the system inspected by an experienced professional.
For more information:EPA Fact Sheet: Preventing Septic System Failure
Penn State Septic System Information
Water Quality Educator
Penn State Extension in Westmoreland County