Water and sewerage

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Sewer systems


Gravity sewer systems

Why install a gravity sewer system?

Gravity sewer systems are considered the traditional method for sewage disposal. They are a good way of collecting and disposing of sewage from properties in areas where the landscape has a gradual slope, a low water table and flooding is rare. 


How do they work?

Gravity sewer systems rely on gradually sloping pipelines to allow the sewage to flow naturally downhill, away from your property and into the collection network. This network ultimately transports flows to a local or regional treatment plant. Refer to the gravity sewer diagram for an illustration of this.

If the area surrounding your property is very hilly, does not slope in the direction required for sewage to flow naturally downhill, or is prone to flooding, a pressure sewer system may be a better solution.


Pressure sewer systems

Why install a pressure sewer system?

Pressure sewer systems are an economical and environmentally friendly way of collecting, transporting and disposing of wastewater from households. They are often used in areas when the landscape is either very hilly or very flat, in areas that regularly flood or have high water tables, or where it is impractical to install other types of sewerage systems.


How do they work?

A pressure sewer system is made up of a network of fully sealed pipes which are fed by pumping units located at each connected property. The pumping unit processes the household wastewater and transfers it to the pressure sewer located in the street via a small pipeline within the property.

The pressure sewer forms part of the overall pipe network which ultimately transfers the wastewater to the nearest sewerage treatment facility – this could be within the surrounding area or many kilometres away. Once installed, the only visible parts of the pressure sewer system are the lid of the storage tank, boundary valve kit and the control panel.


What components make up a pressure sewer system?

The pressure sewer system is made of four key elements which are illustrated in the pressure sewer system components diagram.  These elements are:

  • The pumping unit
  • The boundary valve kit
  • The house service line
  • The control panel


How does the pumping unit work?

The main component of the pressure sewer is the pumping unit, which is installed on the property.  See Page 3 of Using your Pressure Sewer System - an Owners Manual.


Further information

For more information on pressure sewer systems and how they work, please refer to the following documents:

Better sewerage services for your community
This document describes how pressure sewer systems are being applied to backlog sewerage areas.  It includes:

  • A description of the environmental benefits of replacing septic tank systems
  • A list of frequently asked questions
  • The connection process to be followed


Pressure Sewer Information for Plumbers
This document describes the processes involved in organising pressure sewer connections for backloge sewerage areas.


Using your Pressure Sewer System - an Owners Manual
This document is for customers who already have a pressure sewer system. It includes:

  • How to care for the unit
  • What happens if the alarms sound
  • What procedures need to be put in place before going on holidays