Where DOES That Waste Go?

By Karen K. Filchak, Extension Educator, Family and Community Development, Residential Water Quality, UConn Extension

septic field
Septic Field. Photo: UMaine Extension

If you are a property owner with a septic system, it is important to know some basics about the care and management of this waste treatment system. You can be best prepared to maintain it and prevent problems down the road if you understand how the system operates. When sized properly and well maintained, these on-site sewage disposal systems can last for decades.

The purpose of a septic system is to collect, treat and dispose of wastewater on site so it can percolate into the ground without clogging the soil or contaminating ground or surface waters. The main components of the system are the tank and leachfield (also called drainfield or absorption field).

The septic tank serves several key functions. Through settling of the waste, it separates and stores solids. Lighter solids float (scum) and heavier solids settle (sludge). The remaining waste material in the tank is the wastewater (effluent). The tank is designed to allow wastewater to exit the tank while solids remain. Though some limited decomposition of the solids will occur, the tank is designed to temporarily hold the solid waste. It then needs to be pumped out of the tank to allow adequate storage for continued use.

A primary measure of a tank’s effectiveness is its ability to prevent solids from entering the leachfield. Routine pumping keeps the tank functioning as designed. Failure to pump can result in solids entering the leachfield, clogging drains and potentially leading to costly repairs or replacement.

It is generally recommended that the tank be pumped every 2-3 years. Depending upon the size of the tank and number of people in a household, it may vary. (To receive a digital copy of the chart, email Karen.Filchak@uconn.edu). Some communities have regulations that require pumping at set intervals and may require a document to prove that it has been done. When the tank is being pumped, it should also be inspected for the overall integrity of the tank as well as the baffle system. The baffles are important as they slow the water as it enters the tank, resulting in less disruption of the settling process. As effluent is leaving the tank, the baffle helps to prevent solids from leaving the tank and potentially causing a system failure.

The question of additive use is a common one. Many state health departments and the US Environmental Protection Agency recommend against use of additives. Bacterial additives are simply not necessary as there is enough bacteria naturally present. Other additives may actually HARM the system by breaking down solids to a size that can exit the tank as effluent but be large enough to clog the drainage system.

The best method to protect your system is to routinely have it pumped and inspected on a routine basis.