The purpose of a septic system is to treat household waste in areas where public sewers are not available. There are a number of variations in septic system design, but all basically work the same. A basic septic system consists of a large concrete or plastic tank, and a distribution box followed by a series of leach fields.

Whenever you turn on a faucet, flush the toilet or do a load of laundry, the waste leaves the house through the main sewer line and enters the septic tank through the inlet pipe. While the heavy solids sink to the bottom forming a layer of sludge, the lighter solids float to the top.

The bacteria living inside the tank eats the solids and reduces their volumes. Solids are prevented from exiting the tank by devices called baffles, which are located near both the inlet and outlet of the septic tank. The remaining liquids flow through the septic tank and out to the distribution box where they are filtered through leach fields into the soil.

Homesite that are small, hilly or to close to other structures may need an alternative septic system installed.