Wet weather events
When it rains you will see a lot of water around your property and streets, which is all the rain entering the storm water network. During a large wet weather event when there is a lot more rain, some of this rainfall can make its way into our wastewater network.
Our wastewater network is designed to take minor additional flows during wet weather, however in some wet weather events this allowance can be exceeded and lead to overflows from our wastewater network. This problem can be exacerbated if the rainfall is heavy enough to overwhelm the stormwater network, as more may spill over into the wastewater network.
What you will see
You may see wastewater overflowing at designated overflow points along the network, in some cases they occur at maintenance holes or on private property. These wet weather overflows are highly diluted as they are mostly rainwater.
Wet weather overflows in your street
The overflows you see in your street will be highly diluted but please stay clear and call us on 1300 086 489.
We get a lot of calls during wet weather events and our response times may vary but our crews will attend once it is safe to do so, and they will:
- contain the spill, clean and disinfect affected areas
- barricade affected areas if wastewater spills are ongoing
- where overflows occur in a public area or waterway, we will assign specialist environment staff to conduct sampling and monitoring and erect signage to advise the public of the overflow.
Always stay out of flood-affected waters during and after a storm, as they can be fast-moving and may contain snags, sharp objects, stormwater-diluted sewage, chemical waste, fallen powerlines and wildlife.
Wet weather overflow questions
During wet weather, rainfall can make its way into the wastewater network through ORGs (Overflow Relief Gullies), joints in pipes and maintenance holes, and through incorrectly plumbed stormwater drainage.
This problem can be exacerbated if the rainfall is heavy enough to overwhelm the stormwater network, as more may spill over into the wastewater network.
Rainwater and groundwater enter the wastewater network in two ways:
- Inflow – when rainwater enters the sewerage network via defective or non-compliant plumbing.
- Infiltration – when groundwater enters underground infrastructure via cracks and faulty joints.
We inspect wastewater infrastructure in areas where overflows have been experienced, as part of our sewer network testing program.
We notify property owners of any incorrect plumbing connections identified on their property and advise how these can be rectified.
Our crews will also work to identify and rectify any leaks and cracks in underground infrastructure.
- Check your downpipe is connected to the stormwater system, not the wastewater network.
- Check your Overflow Relief Gully is not covered or blocked and the grate is loosely fitted.
The wastewater network and stormwater network are two separate systems, designed to meet different needs.
Unitywater manages and maintains the wastewater network, which contains and transports wastewater from homes and businesses to a treatment plant, where it is treated and either reused or released safely back to the environment.
Councils manage and maintain the stormwater network, which directs rainwater run-off from rooftops, roads, pavements, and other natural and urban areas to the nearest waterway.
