Our Water Supply

Our water supply

The Central Coast has the third largest urban water supply system in NSW. It serves the region’s population of more than 342,000 people, delivering water to more than 135,000 homes and businesses. 

The system has: 

  • three dams 

  • three weirs 

  • three water treatment plants 

  • over 50 reservoirs 

  • 2,200 kilometres of pipelines. 

The region’s drinking water is drawn from Wyong River and Mangrove, Mooney Mooney and Ourimbah Creeks.  

Our dams 

Mangrove Creek Dam 

The Coast’s largest dam is 50km north-west of Gosford in a narrow valley on Mangrove Creek. Built 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.  Water can be pumped into the dam from Wyong River via a pipeline between Mangrove Creek Dam and the smaller Mardi Dam. 

Mardi Dam 

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

Mooney Mooney Dam 

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

Key pipelines 

Two key pipelines help to increase our water storage. Work on a third pipeline will begin in early 2020.  

Mardi-Mangrove Link  

Completed in 2012 at the end of the Millennium Drought, this pipeline provides a significant addition to our ability to capture water and recover from future droughts. It links Wyong River and Ourimbah Creek to Mangrove Creek Dam, via Mardi Dam. During times of high river flow, water can be transferred to the large Mangrove Creek Dam for storage, instead of allowing it to flow to the ocean. 

The Mardi-Mangrove Link pipeline includes: 

  • a 2.1km buried water pipeline from Wyong River to Mardi Dam 

  • a 19km buried pipeline from Mardi Dam to the existing Bunning Creek Tunnel at Mangrove Creek Dam, running through Yarramalong Valley 

  • a new pump station at Mardi Dam 

  • a new pump station beside Wyong River 

  • associated works. 

Hunter Connection 

Water can be transported into the system by the Hunter Connection. This two-way pipeline provides additional water during drought or for operational reasons for 

both the Central Coast and the Hunter regions. 

Mardi to Warnervale Pipeline 

Construction will begin in early 2020 on a pipeline to increase the water supply to the rapidly growing Warnervale area. The pipeline will allow further water sharing between the Central Coast and Lower Hunter, improving water resilience for both regions. The pipeline is expected to be completed by 2022. 

Other water sources 

The water supply is also supplemented by groundwater borefields at Woy Woy and other minor groundwater sources. Other new sources of water include 

stormwater harvesting and recycled water.


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