December 2021 - How does an Emergency Relief Structure work?

Emergency Relief Structures are used to help prevent wastewater overflows from being released through maintenance holes or private plumbing connections.

They are effective in protecting the wastewater system from damage, particularly during extreme wet weather - by stopping uncontrolled wastewater overflows to protect homes in low lying areas, and the wastewater system from being damaged.

Sydney Water’s wastewater system is designed to have additional capacity to contain extra stormwater flows entering the system during and after heavy rainfall. Though in extreme wet weather events, wastewater flows can exceed the system’s capacity. This leads to the mixed increase of wastewater and stormwater flows discharging at the designed overflow points through the Emergency Relief Structures.

The repairs and upgrades to our Emergency Relief Structures will ensure that we continue to provide a safe and reliable wastewater system to protect the environment and the health of our communities.

We have constructed new head walls and screens to improve our Emergency Relief Structures - to help them blend in with the local environment and improve how our wastewater system operates.

See photos of the work we have recently completed in Dundas, within the Mid Parramatta catchment.