A septic tank is a system for the treatment of sewage, and includes all tanks, beds, sewers, drains, pipes, fittings, appliances and land used in connection with the system.

Options such as wastewater treatment plants and composting toilets are therefore types of septic tank systems. A septic tank system treats and retains sewage (toilet water) and sullage (bath, shower and sink water etc.) within the boundaries of your property.

To install or alter a septic tank system in an unsewered area, property owners are required to apply for consent from the City.