How Your Septic System Works

septic tank diagram

The Basic Septic System

  • The septic system is a compact waste water treatment plant buried underground. It consists of a septic tank and an effluent (water) leaching system. These vary in form from leaching fields, leaching trenches, to leaching pits. The sole purpose of the leaching system is the dispersal of household water back into the soil.
  • The septic tank is a water-tight container in which waste matter is collected and decomposed through bacterial action. The tank is usually made of precast concrete, reinforced fiberglass, or cement blocks.

How Your Septic Tank Works

  • Household water and waste enters the tank each time any facility is used.
  • Organic materials float on the surface and form a layer which is called “The Scum Cap.” The bacteria in the tank biologically break down this organic matter into liquid.
  • Inorganic materials as well as the bi-products of bacterial breakdown fall to the floor of the tank and form a layer called “sludge.”
  • Between these 2 distinct layers in the tank lies mostly clear water. In a properly maintained tank, it is the only water that exists and flows into your leaching system.
  • Solid materials overflowing into the leaching system should be avoided. This results in contamination of leach with solids, clogging of the leaching system, or total leach failure.
  • Bacterial deficiency or lack of sludge and scum removal (regular maintenance) is the primary causes of solids over-flowing into the leaching system.
  • Your septic tank is a water tight container. Organic matter that enters and is then broken down by bacterial action to sludge is not biodegradable and will not decompose any further than to the sludge stage. It cannot exit from the tank except via the outlet pipe to the leaching area. If material is not removed through regular pumping, accumulation will occur causing clogging and leach failure.

Leaching Systems

As previously stated, leaching systems vary in design from leach field, to leach trenches, to leach pits. The type and size of leach field is determined by the designing engineer relative to the size of the household it is to service. The purpose of the leach system is the dispersal of household waters back to the soil. If your tank is properly maintained, you will avoid contamination of the leach field with solids and prolong the overall life of your septic system.