Overflow relief gully

An overflow relief gully (ORG) is an essential part of your property and our wastewater network.

It’s the grate-covered drain-like fitting connected to the external plumbing outside of your home.

They’re designed to allow wastewater to spill outside your house in the event of a sewer blockage.


Overflow relief gully diagram
Overflow relief gully diagram

How does an ORG work?

If a property connection drain or sewer main becomes blocked, the ORG is an exit point, releasing sewage outside of your home, preventing it from entering your house.

The ORG is fitting with a loose fitting grate that should pop open to allow backed-up sewage to overflow.

What do I need to do to maintain my ORG?

Keep your ORG clear of landscaping, garden beds, pot plants and other items at all times.

Regularly check the metal or plastic grate covering the gully can easily pop-off to allow an overflow to occur.

Never cover your ORG as this may prevent it from working in an emergency.

Who’s responsible for maintaining ORGs?

It’s up to the property owner to make sure their home is fitted with a properly designed and operational ORG.

If you don't have one or it needs reparing, contact a licenced plumber. All costs are the responsibility of the property owner.

Are ORGs covered by regulations?

Plumbing regulations apply to the installation of ORGs (National Plumbing Code AS 3500 1998).

ORGs must be installed at least 150mm lower than the lowest fixture connected to the drain, and at least 75mm above the ground to prevent stormwater flowing into them.