Preventing Sewage Overflow

Illustration of an overflow relief gully next to an overflowing toilet

Keep your overflow relief gully clear

Homeowners can take a few simple steps today to prevent a potentially complicated, messy and costly problem - sewage overflow inside your home.

All properties have a plumbing device designed to protect your home from sewage overflow. This is called an overflow relief gully (ORG), and it is important to know what it looks like and how to keep it clear and functional.

The purpose of an overflow relief gully is to release any sewage overflow away from the inside of your home. If the ORG is covered or not working properly and a pipe gets blocked, raw sewage can overflow from your toilet and into your home.

To avoid sewage overflowing inside your home, the main thing to remember is to keep the ORG clear of any obstructions. Do not place pot plants or tiles etc on top of it.

If your ORG is set too low or your property is in a low-lying area, it can flood and contribute to stormwater entering the sewer system. Improper stormwater connections from downpipes or water tanks being connected to ORGs or sewer pipes can also contribute to stormwater inflows.

Steps you can take to prevent sewage overflow

First of all, find your overflow relief gully. Every home has one. It will be located outside, usually near the laundry or bathroom wall, or at the end of the house sewer system.

Check the overflow relief gully is at the right level:
- 150mm lower than the lowest waste outlet fitting in the house
- 75mm above the surrounding ground to ensure that stormwater does not flow directly into the ORG
Check the top/grate isn’t jammed shut or stuck down – it needs to be loose so that it can pop off easily
Remove anything sitting on the top – pot plants, buckets etc - so that sewage overflow can be directed outside in the case of a pipe blockage.
Keep clear of roof drain pipes and any paving or landscaping sloping towards it to prevent anything gravitating into the system i.e. stormwater run-off etc.

If you are unsure if your ORG is compliant, please contact your local licenced plumber.