About Council

Somersby Water Treatment Plant Capital Works Project

Over $30 million will be invested by council in over the new 20 years to improve the Somersby Water Treatment Plant (SWTP) and ensure the community continues to receive safe and reliable drinking water.

A strategic review undertaken in 2011 by Hunter Water Australia identified augmentation and renewal requirements to meet current and future water supply needs through to 2031.

These requirements have been assembled into a 20 year capital works plan (CWP). Around 150 projects are planned to be delivered at the plant between now and 2031.

About the SWTP

The SWTP is responsible for producing most of the 11 billion litres of drinking water council supplies each year to around 70,000 properties currently using its water supply network.

The plant currently has the ability to produce around 144 million litres of water each day and treats raw water from the Lower Mangrove Creek Weir, Mooney Mooney and Mangrove Creek dams, as well as the Somersby and Narara bores.

Augmentation and renewal requirements will allow the plant to continue to meet Australian Drinking Water Guidelines now and into the future.

Community benefits

Improvements to the plant will result in:

  • Improved water quality;
  • Security of supply; and
  • More cost effective operation.

Project status


Description and status

Filter refurbishment

  • Includes filter media and nozzle replacement; replacement of valves and control system; replacement of air delivery pipe work and improvement in air scour system; and safety improvements including widening of walkways, provision of self closing gates and double isolation.
  • The project is 80% complete.

Replacement of sludge scrapers

  • Two of four sedimentation tanks have had their 40 year old travelling bridge sludge scrapers replaced with leading technology, Zickert Z2000 by Nordic Water. First of their kind to be used in a water treatment plant in Australia, the new scrapers are performing well. Sludge scrapers play an important role in the treatment process by helping remove particles from the water.

Electrical and control system upgrade

  • Includes two new and one refurbished switch room; installation of a communications pole; replacement of switchboards and control panels; installation of a pit and conduit system with new electrical cabling and a fibre optic ring main to service all assets across the plant safely and reliably.
  • All works complete except for switch room two switchboards and transferring cabling to equipment from the old boards to the new boards.

Pumps and pipe work

  • Alum and polymer chemical dosing pumps and manifolds replaced, providing spare capacity.
  • Chemical dosing lines replaced and flow metering provided for improved operation.
  • Utility pumps replaced with a more streamlined and economical arrangement.

Flash mixers

  • Replacement of flash mixers with improved energy efficiency.


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