Overflow Relief Gullies

What is an overflow relief gully (ORG)?

An overflow relief gully (ORG) is a plumbing device located outside your house. It is designed to release sewage to your garden should there be a blockage in your pipes or drains.

Should a sewer blockage cause sewage to back-up into your pipes, the grate that covers the top of the ORG will pop-out to release sewage outside your home. This will keep the interior of your house and its content safe from 'nasty surprises'.

To protect your home, you need to ensure the ORG can function properly in an emergency.

  • Check that the top of the ORG is uncovered and can easily pop-out to allow sewage to escape. Obstructions such as pot plants, palm fronds and other garden debris may prevent it from working correctly.
  • Make sure that water from your roof downpipes, landscaping run-off or pool backwash is not diverted into your ORG. Excess water entering the sewer system can cause pipes to become overloaded which may lead to sewage overflows.


What does an ORG look like?

An ORG is a drain-like fitting made of plastic or metal alloy located outside your house; usually close to your bathroom or laundry external wall. ORGs can look different on various properties and must not be confused with stormwater drains.

ORGs can look different on various properties 

How should my ORG be installed?

There are plumbing standards that regulate the installation of ORGs and dictate that an ORG should be installed:

  • at least 100mm lower than the lowest waste outlet in your home (eg. basin, shower or toilet)
  • at least 150mm above the surrounding ground to prevent stormwater flowing into it.

Correct installation of an ORG

What not to do?

Property owners are responsible for the maintenance and repairs of sewer connections and fittings around their house up to the sewer connection point. It is essential that you keep your ORG in good condition so it can play its part in protecting your home from spills and keeping the sewer network free from blockages.

These are examples of incorrect connections of ORGs commonly found in backyards: Incorrect connection of an ORG

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