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Water supply services
The Central Coast has the third largest water supply system in New South Wales. Find out about our dams and catchments and water storage levels.

Council service the whole Local Government Area with a population of approximately 345,000, delivering on the following key areas to more than 139,000 homes and businesses:

  • Harvesting raw water - catchment, storage, treatment
  • Providing drinking water - treating water delivered to customers
  • Collecting sewage - transport, treatment and discharge
  • Recycling treated water – advanced sewage treatment and reuse
  • Managing stormwater – flood mitigation, stormwater conveyance and water quality

Water is drawn from streams at Mangrove, Ourimbah and Mooney Creeks and Wyong River and collected in dams at Mangrove Creek, Mooney Mooney and Mardi, as well as weirs at Wyong River, Ourimbah Creek and Mangrove Creek.

The Mardi-Mangrove Link transfers water from Wyong River for storage in Mangrove Creek Dam. The link means that during high flows, water can be transferred to the large Mangrove Creek Dam for storage, instead of allowing it to flow to the ocean.

We have six bores that extract water from below the ground. Water also is transported into the system by the Hunter Connection. This two-way pipeline provides additional water for operational reasons, or during drought, for both the Central Coast and Hunter.

There are water treatment plants  at Somersby and Mardi, and another at Woy Woy that treats water from groundwater bore fields in the area. These plants deliver top quality water to your taps.

We also have a comprehensive guide that can help with water and sewer maintenance and repairs including what to do case of a leak, discoloured water, sewer block or overflow.

For more information, please see our Central Coast Water Supply System brochure.

Water storage levels

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Total Central Coast water usage

Current dam water storage levels

Water demand ML/week

Dams and catchments

Mangrove Creek Dam

Mangrove Creek Dam is the Central Coast’s largest dam, located 50 km north-west of Gosford in a narrow valley on Mangrove Creek. Constructed between 1978 and 1982, the dam provides 93 percent of the region’s water storage. Mangrove Creek Dam is a large storage dam, not primarily a collection dam.

Construction type: Concrete faced rockfill  
Built: 1978-1982  
Maximum capacity: 190,000 million litres (ML)  
Height: 80 metres  
Catchment area: 101km²

See our Mangrove Creek Dam Brochure for more information and historical photos.  
See our Mangrove Creek Dam Safety Emergency Plan Summary for more information about dam safety and emergency response procedures

Mardi Dam

Located 4km south-west of Wyong, Mardi Dam was built in 1962. Mardi Dam is an offstream storage facility, meaning it is not fed directly by a stream and must be filled by pumping water from Wyong River and Ourimbah Creek.

Construction type: Earth fill  
Built: 1962  
Maximum capacity: 7,400ML  
Height: 26 metres  
Catchment area: 4 km²

Mooney Mooney Dam

Built in 1961, Mooney Mooney Dam is the region’s oldest dam and located around 10km north-west of Gosford. Water is pumped to Somersby Treatment Plant and then to residents.

Construction type: Concrete arch  
Built: 1961  
Maximum capacity: 4,600ML  
Height: 28 metres  
Catchment area: 39 km²

Dams Safety

Dams Safety NSW requires all owners of declared dams to submit an Annual Dams Safety Standards Report. The reports are required to provide information on a dam owner’s level of compliance with the Dams Safety Regulation 2019. The report also provides important information to Dams Safety NSW to enable them to prioritise compliance activities. 

Water catchments

A catchment is an area where water is funnelled by the natural landscape into a creek, river, lake, into the groundwater system or to the ocean. Managing and protecting our catchments effectively is a key process for ensuring good raw water quality. The fewer contaminants reaching water in our dams, the fewer our treatment processes have to take out.

Access to the area directly surrounding the Central Coast’s dams is restricted. This buffer zone helps to prevent nutrient runoff and other substances that could affect the quality of water, from entering the dam.

Limiting access to the dams will help by:

  • protecting raw water quality
  • protecting large areas of bush land and plant and animal habitats
  • protecting threatened plants and animal species
  • preserving evidence of Aboriginal occupation dating back many thousands of years.
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