Maintenance activities have been programmed as part of Water Quality 2010 to reduce the likelihood of discoloured water events. Council pays particular attention to cleaning pipes within the water supply system using methods such as flushing, swabbing and jetting.  

Flushing

Council cleans the smaller water mains, which feed water into your taps, by pushing water through them at a high velocity. This process is known as flushing.

The high pressure water removes discoloured water-causing material from within the pipes and is released through hydrants located at the end of the water main.

With the introduction of water restrictions in 2002, Council reduced its mains flushing activities to help conserve water. With storage levels increasing, Council is able to apply more focus on water quality and has developed an ongoing flushing program as part of Water Quality 2010 which aims to balance water conservation and maintenance of water quality levels.

The first phase of the Water Quality 2010 flushing program was completed in early 2008, successfully removing discoloured water-causing material from water mains across the region and significantly reducing the number of water quality complaints. Council has incorporated mains flushing into its ongoing maintenance activities and is currently undertaking the second round of the program to provide added protection against discoloured water.

Swabbing

The larger water mains in our water supply system, which convey water from the treatment plant into the network of service reservoirs and smaller water mains, are being cleaned by a process known as swabbing. This process involves pushing a bullet-shaped foam swab along the water main under water pressure.

The swab scours the walls of the water main to remove any discoloured water-causing material lining the pipe. The water containing this material is then removed from the water main.

Since Water Quality 2010 began in October 2007, Council has swabbed the large water mains from our treatment plant at Somersby through Kariong, to Koolewong. In 2009, Council plans to clean mains from Somersby to North Gosford and from Koolewong to Woy Woy.

Other technologies

Council has also trialled other cleaning technologies as part of Water Quality 2010, including jetting and a sound-wave technology system, to find the most cost-effective and efficient method of cleaning water mains.

Jetting

During jetting,water is sprayed onto the inside wall of the water main at high velocity through a special nozzle attached to a hose. The water pressure removes discoloured water-causing material lining the walls of the main to reduce the risk of discoloured water. This method is used in locations where swabbing is difficult.

Sound wave technology

Sound wave technology, also known as Anti-Bio, transmits low frequency sound waves and electromagnetic fields into water mains to remove and prevent further formation of a lining on the inside wall of water mains. Initial trials of this technology did not reveal it to be the most effective means to clean Gosford's water mains and it will not be implemented during Water Quality 2010.

Visit our upcoming water supply works schedule for more information on planned and current water supply works in your area.

See also:

Drinking Water Quality
Understanding your drinking water
Water Quality 2010