Gravity sewer systems

A gravity sewer connection or disconnection application may be submitted by the property owner, or a person that has authority to act on behalf of the property owner (e.g. plumber, builder, managing agent).

Location of the sewer main

Where practical, we provide an individual gravity sewer connection point to each separate lot. This sewer connection point is normally located within the boundaries of the lot and sized 150mm.

For gravity sewer connections the sewer main will be:

  1. Within the property
    The sewer point of connection is the arm of the junction located in our sewer main within the customer’s property. The junction is sealed at the time of construction. We own the junction and adjacent sewer main; or
  2. Outside of property
    The sewer point of connection is located at the end of a branch/sideline from the sewer main terminating within the customer's property.
    We may specify a 'Y-junction' at the end of the sideline to which the property connection is to be made to the branch of the junction. This is to allow future maintenance or possible extension from the straight line section of the junction. We own the branch/sideline and 'Y-junction'.

Water and Sewer Design Manual

We adopt the Water Services Association of Australia (WSAA) design manual for construction of gravitational sewers, which nominates the minimum depth of the sewer point of connection as normally installed at a depth that allows the most efficient drainage of the lot.


Connecting to a gravity sewer system

Follow our three step process to connect a gravity sewer system.

What you need to know

If the property owner, builder or managing agent is to make the application to connect, it is your responsibility to ensure all applications have been submitted and inspections booked prior to any physical water connection works.

Disconnecting from a gravity sewer system

Where a property’s sewer service has become redundant, or is not to be redeveloped and becomes disused, it can be disconnected from our sewer system. Disused sewer services are to be sealed off at the point of connection using approved materials in the accordance with AS/NZS3500.2 Plumbing and Drainage and our requirements.

Follow our three step process to disconnect a gravity sewer system.

Sewer soffit requirements

The soffit is the highest point of the internal surface of a pipe. There are minimum measurements between the soffit of the sewer main and the spill level of the overflow relief gully (ORG).

Thirsty for more advice?

If you need more advice on gravity sewer systems, get your questions answered by contacting our Technical Services team.