The Overflow Relief Gully / House Drains

What Is An Overflow Relief Gully?

An Overflow Relief Gully (ORG) is a drain-like fitting located outside the home, that allows sewage to overflow away from the interior of your home and outside to the garden if there is a sewer blockage.

How Does It Work?

If a sewer blockage occurs, the ORG fitting should pop off to release the pressure and direct sewage away from your home. It is the home owner’s responsibility to make sure their home is fitted with a properly designed and operational ORG. When an ORG is not functioning correctly the property damage and health risks associated with sewage spilling inside or under a property are greatly increased. 

Make sure your Overflow Relief Gully is not:

  • underneath the property as a result of not being moved when a house extension was built (a plumber should move the existing ORG as part of constructing a house extension)
  • blocked with concrete as a result of driveway or paving construction
  • covered by landscaping or garden beds
  • covered by any objects
  • unable to pop off because it is corroded, filled with silt or concreted in
  • a model which requires manual twisting in order to pop out.

Make sure your Overflow Relief Gully has:

  • a clear drainage path (so spills drain away quickly without causing damage)
  • a fitting that can pop off completely
  • been installed at the correct level*
  • at least 150mm lower than the lowest fitting in the house (e.g. basin, shower, toilet, etc) and usually 75mm above the surrounding ground.