Understanding what an overflow relief gully is, why Australian regulations require it, and how to maintain it properly can save you from costly damage, health hazards, and a genuinely unpleasant situation.
Overflow Relief Gully Explained
An overflow relief gully (ORG) is a plumbing device located outside your home that’s connected to your house drainage system. It’s typically made of plastic or metal alloy and ranges between 100 and 150mm in diameter. The distinctive feature of an ORG is its loosely fitted grate on top, which is specifically designed to pop off completely when pressure builds up in the system.
In the event of a sewer blockage that causes wastewater to back up through your drainage system, the ORG acts as a pressure release valve. Instead of sewage overflowing inside your home through your toilet, shower, or floor wastes, it escapes outside through the ORG, confining the mess to your garden rather than your living spaces.
According to Barwon Water, most properties constructed after 1976 have an ORG, though older homes may not unless additional work has been undertaken. Over the years, various styles of ORGs have been installed, all meeting performance standards at their time of installation.
Not sure if your home has a compliant overflow relief gully? Contact Ezy-Plumb today for a professional assessment of your drainage system and ensure your home has the protection it needs.
Why Australian Regulations Require an ORG
The Plumbing Code of Australia and the AS/NZS 3500 series of standards, which govern sanitary plumbing and drainage systems, stipulate specific requirements for overflow relief gullies.
The primary regulation states that every home must have an overflow relief gully installed at least 150mm below the lowest fixture in the house. This is typically the shower base or floor waste, as these are usually the lowest wastewater discharge points in a residence.
The Victorian Building Authorityemphasises that this minimum vertical separation of 150mm between the lowest fixture and the spill level of the ORG is essential to ensure the dwelling is protected from sewer surcharge. Without this clearance, the ORG can’t function properly and sewage would reach your internal fixtures before it could overflow outside.
How Does an ORG Protect Your Home?
When everything’s working normally, you’ll probably forget your ORG even exists. But when disaster strikes in the form of a blocked sewer, this humble fitting becomes your home’s first line of defence.
Sewer blockages can occur for various reasons: tree roots infiltrating pipes, inappropriate items flushed down toilets, accumulated grease and debris, or even heavy rainfall overwhelming the system. When a blockage occurs, wastewater has nowhere to go and begins backing up through the drainage network.
Because the ORG is positioned lower than any internal fixture, the rising sewage reaches it first. As pressure builds, the lightweight grate pops off completely, allowing the sewage to spill outside into your garden or yard. Whilst an outdoor sewage spill is certainly unpleasant and requires immediate attention, it’s infinitely preferable to sewage erupting through your shower, toilet, or floor drains inside your home.
The Queensland Building and Construction Commission> notes that the top of the gully must not be enclosed and must have clear access for more than 2 metres above the grate. This ensures nothing impedes the overflow function when it’s needed most.
Maintaining Your ORG
Maintaining your ORG is your responsibility, not your water authority’s. The property owner is responsible for all plumbing and drainage infrastructure from the house to the point where it connects to the main sewer line.
Keeping your ORG functional is remarkably straightforward:
- Never cover your ORG with tiles, concrete, decking, or paving. Don’t place pot plants, garden furniture, or storage items over it. The grate needs to be able to pop off freely when pressure builds, and you need easy access to clean it regularly.
- The area around your ORG should allow overflow to drain away from your home’s foundation. If water pools around the ORG, it’s not providing adequate protection.
- Every few months, have a quick look at your ORG. Make sure the grate isn’t rusted, stuck in place, or filled with debris. Give it a gentle lift to ensure it moves freely. Remove any leaves, dirt, or silt that might be blocking the grate.
- If you notice slow-draining fixtures throughout your home, gurgling sounds from drains, or unpleasant odours near the ORG, these could indicate a developing blockage. Don’t wait for an overflow and call a licensed plumberimmediately.
Experiencing drainage issues or concerned about your ORG’s condition? Call Ezy-Plumb now for prompt, professional service - 0402 169 096
Trust Ezy-Plumb for Your ORG Needs
If you’re unsure whether your home has a compliant ORG, if you’re planning renovations that might affect drainage levels, or if you simply want peace of mind that your plumbing protection is adequate, contact Ezy-Plumb today. Our licensed plumbers can assess your ORG, ensure it meets current Australian standards, and provide expert advice on maintaining this crucial piece of infrastructure.
FAQs
Q: Where is the Overflow Relief Gully located?
A: You’ll usually find it outside, somewhere near your bathroom, kitchen or laundry wall, and it needs to sit at least 150mm below your lowest drain inside.
Q: How do I know if my Overflow Relief Gully is working properly?
A: The grate should come off easily when you lift it, the whole area should be clear with nothing blocking it, and there shouldn’t be any debris or rust stopping it from working.
Q: Do all Australian homes need an Overflow Relief Gully?
A: According to the Plumbing Code of Australia (AS/NZS 3500), every household should have one as part of their drainage system.
Q: Can I cover my Overflow Relief Gully with paving or decking?
A: It needs to stay uncovered and accessible with clear space above it so it can actually do its job when there’s a blockage.
Q: What should I do if sewage overflows through my Overflow Relief Gully?
A: This indicates a sewer blockage. Contact a licensed plumber immediately to clear the blockage and prevent further overflow or damage.
A: That means you’ve got a sewer blockage. Ring a licensed plumber straight away to get it cleared before things get worse.
