How to fix overflow relief gullies filled with sand?

Hi all. I have recently moved into my first home, and there is a fair bit of work that needs doing.

I am trying to understand why the bathroom smells. I have tried to bleach and run hot water down the pipes, but have noticed all the overflow relief gullies have been filled with sand, and debris.

I can’t seem to understand why this would be done? What benefit would it have, and does these run into the main sewage? Any help would be appreciated.

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MitchellMc

Welcome to the Bunnings Workshop community @Firsthomediyer. It's terrific to have you join us, and many thanks for your question about relief gullies.

Great question—and congrats on your first home! It does sound like there’s a bit to investigate.

The overflow relief gullies (ORGs) should be connected to the sewer or, they could be inspection outlet for the stormwater, depending on the system setup—but they should definitely not be filled with sand. If you dig down a bit, can you see whether the pipe continues downwards, or is it just the inspection outlet at the top? That’ll help determine if it’s a functioning drain or just a capped off section.

It’s hard to imagine someone would purposely fill them with sand. The only plausible reason I can think of is that the gully might not actually be connected to any pipework below, and you’re actually seeing fill sand or soil from underneath the slab—maybe an abandoned or incorrectly finished outlet.

If the ORGs are blocked or not properly venting, that could explain the smells you're experiencing in the bathroom.

Please let me know if you have any questions.

Mitchell

Firsthomediyer

Thanks for the reply Mitchell, so I have a few different types of drain:

These, that sit flush to the floor, and appear to of been filled with debris. Unsure if these are ORGs? They also have pipes leading from the floor trap in the bathrooms, which have been covered. Like so:

Then I also have these which I’m assuming are definitely ORGs, with standing water in (They have not been filled with sand/debris)

MitchellMc

Hi @Firsthomediyer,

ORGs are supposed to be clear so they can safely relieve overflow and prevent sewage backing up into the house.

There’s no real benefit to filling them with sand — it’s likely someone did it to try and block smells temporarily, or just didn’t know what they were doing. They do connect to the main sewer line, so keeping them clear is important.

I'd recommend clearing them out properly and giving the drainage system a good flush. If you’re still getting strong smells after that, it might be worth getting a plumber to check for any deeper blockages or broken seals.

Mitchell

Firsthomediyer

Thanks Mitchell, do you think both are ORGs? The drain that sits flush to the ground too?

EricL

Hello @Firsthomediyer

Yes, I suspect that both of them are ORG's. I agree with Mitchell's recommendation of getting a plumber to inspect and unblock the ORG's this might also free up the smell from your bathroom.

If you need further assistance, please let us know.

Eric

Firsthomediyer

Great thanks!

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