There are two wastewater treatment plants in the Westernport region. These process 1100 megalitres (ML) of domestic wastewater each year.
The Cowes Wastewater Treatment Plant (CWWTP) is the main plant treating 90 per cent of waste by volume. The secondary plant, the King Road Wastewater Treatment Plant (KRWWTP) in Coronet Bay, treats the remaining 10 per cent of waste by volume. Both accept domestic waste only.
The CWWTP can treat up to 8.5 ML per day and the KRWWTP can treat up to 0.35ML per day.
Westernport Water supplies wastewater services to 90 per cent of properties that receive water.