Most water and sewerage pipework is hidden underground, but there is one important piece of sewerage pipework that homeowners should be able to see.
It is an overflow relief gully (or ORG for short), and most properties will have one. If you can’t find it, your property may have a reflux valve installed instead. A reflux valve allows sewage to flow in one direction only and is intended to automatically close when flow reverses. A reflux valve may also be required for a property in a flood zone.
East Gippsland Water General Manager Customer, Community and Communications David Radford said overflow relief gullies are a pipe with a loose grate on top.
“They are usually outside the laundry, kitchen or bathroom,” Mr Radford said.
“If you have moved into a property, it is important to find your overflow relief gully. You want to check that it hasn’t been buried under dirt, and that the grate is loose, not sealed to the pipe.
“The purpose of the overflow relief gully is to prevent a blocked sewer backing up and overflowing into a house. If you do have a blockage, the grate on the overflow relief gully lifts off and allows the sewage to overflow freely outside the house. The grate is there to stop objects falling into the sewer, not to stop material flowing from it,” Mr Radford said.
“The overflow relief gully will be at least 150 mm lower than the lowest drain or toilet in your home. This is so sewerage will reach the grate before it reaches the sinks or toilet in your home. It also needs to be at least 75 mm above ground level – this prevents stormwater flowing into it.”
“It is also important that a property does not connect downpipes or stormwater into the overflow relief gully. The sewerage network is not designed to carry large volumes of water from rain and storms. It can overload the system and increases the chances of sewer blockages and sewage spills during heavy rain,” Mr Radford said.
It is important that the grate on an overflow relief gully is loose.