Overflow relief gullies (ORG)

What is an overflow relief gully?

An overflow relief gully (ORG) is a critical part of your sewerage system. They prevent sewage from flooding your house.

ORG's are:

  • drain-like fitting located in the ground outside your home, usually near the laundry 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 rain water in the sewerage network.

Large houses with a few bathrooms may have more than one overflow relief gully.

This video explains what an overflow relief gully is.

How do overflow relief gullies work?

If a sewer blockage occurs, or the sewerage network can't cope with rainwater during a storm, the ORG fitting should pop off to release the pressure and direct the sewage away from your home. It is the property owner's responsibility to make sure the ORG is properly fitted and maintained.

How should an ORG be installed?

Plumbing regulations require ORG’s to be installed:

  1. So that they sit at least 150mm lower than the lowest household drain. Because they are the lowest point, any sewage that can’t go down the sewers will flow out of this point rather than backing up inside household pipes and overflowing into floor drains.
  2. At least 75mm above ground level to avoid collecting stormwater during heavy rain.

An ORG should only be altered or installed by a licensed plumber.

overflow relief gully

Do all properties have an overflow relief gully?

Properties built before 1976 may not have had an overflow relief gully installed unless some renovation work or improvements have been carried out.

Some older houses may have a disconnector gully or vent. If you have one of these we recommend you contact a licensed plumber who can easily convert them to an overflow relief gully.

How do I maintain my overflow relief gully?

  • The overflow relief gully belongs to the property owner. We recommend you keep your overflow relief gullies and all other plumbing and drainage in good condition and operating correctly.
  • Check overflow relief gullies are not covered by landscaping, garden beds, pot plants or other items.
  • Regularly check that the metal or plastic grill covering the gully can easily pop-off to allow any overflow to occur.
  • Make sure any overflows can drain away quickly so there is no build-up around the gully or house.
  • Check storm water in your yard does not build up and flood your overflow relief gully.

N.B. – Property owners own and are responsible for all internal Plumbing on their property.

ORG Related Links

Sewer Blockages
Sewer Blockages from Trees
How rainwater affects our sewerage system
Plumbing

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