Types of wastewater systems

Property owners are responsible for maintaining the pipes and fittings on their property up to where they connect to our water, wastewater and stormwater networks. This is the point of connection. 

Protecting these pipes is important. Putting the wrong things down the toilet, sink or outdoor drain can block pipes and cause them to overflow. This will cost you money and pollute our environment.

The most common types of wastewater connections are gravity, pressure and vacuum.
Diagram of typical gravity wastewater connection

Most properties have gravity wastewater systems.

Most properties have gravity systems.

Wastewater from each property flows under gravity to the pipe network and then on to a pumping station.

Pipes may need to be laid underneath footpaths, roads, private property or parks to allow the wastewater to flow by gravity.

Pressure wastewater systems use individual pumps in collection tanks installed on each property.

Diagram of typical pressure wastewater system.

Pressure wastewater systems use individual pumps. 

Wastewater from the home or business is pumped from the collection tank to the pipe network in the street. We own and maintain the on-property pump for eligible residential properties and some smaller businesses.

We've been operating pressure systems for many years. Jamberoo, Belimbla Park, Stanwell Park, Coalcliff and Otford were among the first areas to be serviced with this technology.


A vacuum sewer uses a partial vacuum in wastewater pipes to transport wastewater from homes and businesses to a central treatment point.

We've installed vacuum sewers in Kurnell, Bundeena, Maianbar and Palm Beach.

If you have permission to connect to a vacuum sewer, you will have some special conditions of connection and we'll give you a customer agreement.