Preventing Sewage Overflows

Keep your overflow relief gully clear

A few simple steps can be taken by homeowners to prevent sewage overflow inside your home.

All properties have a plumbing device designed to protect from sewage overflow. This is called an overflow relief gully (ORG) and depending on the size of your home, you may have more than one.  

Overflow Relief Gully

Checking your overflow relief gully is compliant

Plumbing regulations apply to the installation of ORG’s. An ORG is:

  • A drain-like fitting located in the ground outside your home, usually near the laundry/bathrooom area.
  • Designed to overflow sewage onto the ground outside your house, rather than inside the home if there is a blockage in your plumbing or excessive rainwater in the sewerage network.
  • At least 150 mm below the lowest internal drain fixture (e.g. bathrooms, toilets and the laundry), and;
  • 75 mm above the surrounding finished ground level (except where the gully riser is in a path or a paved area, in this case it must be finished at a level that prevents rainwater inflow into the wastewater system during rain events).

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

Tips to prevent sewage overflow

ORGs should be kept clear of obstruction such as other plumbing, pot plants, clear of landscaping and debris and should be raised to the correct height above the surrounding ground. ORGs have a grate cover which should be loose and easily popped of if the sewer backs up. In the case that the sewer does back up, the ORG will ensure the overflow is directed through the ORG outside your home. If the ORG is blocked or covered, the sewer back up may overflow inside your home.

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