In most "conventional" septic systems constructed within the last 25 years, the soil absorption system (SAS) consists of either gravity fed trenches or a bed constructed of perforated plastic pipe laid locality, the pipe is commonly 4 inches in diameter with 1/2" to 5/8" holes on 3-to-5 inch centers long the length of the pipe and located 30 degrees above the vertical diameter of the pipe (at approximately  and 7 o'clock or 4 and 8 o'clock). The depth of gravel below the pipe commonly ranges from 6 inches to 12 inches. Soil absorption systems contain either a series of parallel trenches 36 inches wide or a single continuous bed of gravel instead of trenches. Although beds are generally easier to construct, they lack the added sidewall absorptive capacity and capability for atmospheric oxygen transfer provided by trenches.

Even properly designed and installed systems eventually fail; this fact is easy to forget when the system is buried and operating effectively. A failure has a serious effect, however. Sewage backs up into the building or gathers on the ground. People and animals may become ill. Pollution may enter surface waters and shallow drinking water supplies. In addition to public health concerns, there is a costly repair bill. Normal activities are interrupted while the system is uncovered. Properly maintaining your septic tank, including having a regular maintenance & cleaning schedule, will extend the operating life of your septic field and make repairs easier to handle. A good start is knowing how to maintain the septic system and use it wisely.

• Diagram of a Septic System 

• Conventional Septic Systems
• Pump Septic Systems