Overflow Relief Gully

> What is an Overflow Relief Gully?

An Overflow Relief Gully (ORG) is a small drain located in the ground outside your home, usually near the laundry area.

If a sewer blockage occurs, the ORG is designed to release any sewage overflow away from the interior of your home.

In the event of a sewer blockage, the ORG grate should pop off to release the pressure and direct sewage away from the home.

Most properties built since the late 1970s have an ORG installed.

ORG are between 100 and 150mm in diameter and are made of plastic or metal alloy.


> Checking your Overflow Relief Gully

We recommend that property owners check to see if they have an ORG correctly installed.

It is important that your ORG is not covered by a pot plant, garden bed or any landscaping works.

You should also check regularly to ensure it is clear of debris.

The ORG grate must be loose so that it can pop off easily in the case of a sewage overflow.

> Requirements for an Overflow Relief Gully

The ORG should be installed at the correct level, at least 150mm lower than the lowest fitting in the house (e.g. bath, shower etc.) and at least 75mm above the surrounding ground to prevent stormwater entering the sewerage system (see diagram below).

It is the property owner’s responsibility to ensure that a properly designed ORG is installed by a licensed plumber.

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


> What is an Overflow Relief Cap?

An Overflow Relief Cap (ORC) is a device that can be fitted to your existing ORG.

An ORC helps prevent stormwater entering your sewer pipes and allows the Overflow Relief Gully to work as normal in the event of a blockage.

You can ask a licensed plumber whether an ORC is an option for your property.


  Lid should not be covered by any debris or landscaping


  Lid must not be secured down so it can easily pop off


  Should be at least 75mm above the surrounding ground


Above: requirements for an Overflow Relief Gully

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