Inflow & Infiltration Reduction Programme

• It is Council’s responsibility to fix the fault if it is located in pipes from the private property boundary to the wastewater treatment plant; and
• It is a property owner’s responsibility to fix the fault if it is located inside their property boundary.

During heavy storms events, the District’s wastewater treatment plants can receive between two to four times more flow than usual. This is caused by rainwater entering the wastewater network.

This impacts the performance of all parts of the wastewater network. As a result, Council spends money upgrading assets and treating millions of litres of wastewater that doesn’t need treatment.

There are numerous ways that rainwater can enter the wastewater system including:

• gully traps that aren't sufficiently elevated above ground level to avoid rainwater draining into them;
• leaks in wastewater pipes that have developed defects over time; and
• roof downpipes or yard drains diverted into gully traps.

These small problems on many properties can add up to a lot of water piped and treated unnecessarily.

Downpipes are pipes that carry rainwater from a roof to a stormwater pipe, soakpit or water tank.

A compliant downpipe does not discharge to a gully trap as below.

A gully trap is a fixture located against an outside wall of your house. It receives wastewater from your kitchen sink, laundry, bathroom and toilet.

A wastewater lateral is a pipe that carries wastewater from the gully trap to the private property boundary. A broken wastewater lateral will allow rainwater to seep in or cause blockages on your property.

A lateral is a buried pipe that is not visible from ground level. Your plumber or drainlayer will be able to advise you on inspecting and repairing a lateral fault.

Stopping rainwater from getting into the wastewater network will save money for all of us and benefit our environment. Those funds that wouldn't be spent on the overloaded wastewater system can be used to build community infrastructure to improve social wellbeing and reduce rates.

Together we can make a big difference for the benefit of all of us!