A septic tank is a man-made, watertight container for holding sewage. Septic tanks are typically installed to hold domestic wastewater in a residence or commercial building. In some places, septic tanks are required by law to receive any household sewage that enters the drain from plumbing fixtures; in others, it is illegal to pour such waste into a storm drain.
Septic tanks are designed to withstand the weight of the soil above them as well as standing water and to keep contents from leaking out of the bottom. They must also be able to withstand concentrated human waste and other liquids without corroding.
Septic tanks are usually made of concrete, fiberglass or polyethylene plastic. Older septic tanks may be made of wood or metal (such as steel). They can have one or two chambers with an outlet pipe that goes into the drain field or leach field where it is covered with topsoil.
The septic tank needs to be large enough so that it can hold all the sewage from your home for at least a day or two at a time before emptying into your leach field or drainfield (also called soakaway). The average size for a family home is about 3 metres wide by 3 metres long by 1 metre deep.
Last modified: August 17, 2022