Inhabitants supplied

First project of the Water business in Western Australia

The contract includes design, construction and operation & maintenance for 35 years under concession.

The Helena Water consortium, comprising ACCIONA, TRILITY, Brookfields Multiplex and RoyalBank of Scotland, won the tender to design, build and operate the Mundaring drinking water treatment plant in the Perth area (Western Australia) for a 35 year period.


This is a PPP (Public Private Partnership) project in the state of Western Australia. Its initial capacity will be 165,000 m3 per day, with a maximum capacity of around 240,000 m3 per day.

The plant supplies the Goldfields and Agricultural Water System (G&AWS) network, including Kalgoorlie, in the State of Western Australia. Australia's G&AWS is the drinking water supply network serving more than 100,000 people. It has more than 530 km of pipelines originally built in 1919.

The plant takes raw water from the Mundaring reservoir and then treats it to achieve the correct pH level.


  • Entity: Water Corporation
  • Location: Mundaring, Western Australia
  • Population Served: 100,000 inhabitants
  • Flow: 165,000 m3/day


  • 3 power supplies
  • Raw water pumping
  • Chemical treatment and flocculation
  • Flotation - filtration: DAFF
  • Activated carbon filtration (BAC)
  • Dissolved Organic Carbon Removal (DOC)
  • Ultraviolet and chloramines disinfection
  • Recarbonation
  • Sludge treatment
  • Product water pumping
  • 24/7 security of supply
  • Australian Drinking Water Guidelines (ADWG) compliance
  • Low corrosive product water for distribution pipework
  • Disinfection control


Key figures


inhabitants served


m3 per day


years of D&C and O&M contract

Management of environmental impact

Control of invasive species

Oceania's fauna is unique in the world and is severely affected by invasive species.


One of the issues that has been controlled is the spread of the oomycete Phytophthora cinnamomi fungus, which has seriously affected forests in the project area and has had a very negative impact on the natural vegetation. This fungus is included in the list of the 100 most damaging invasive exotic species in the world by the International Union for Conservation of Nature (IUCN).


A full protocol on the arrival and use of pine timber has also been drawn up, as the Hylotrupes bajulus beetle is a pest that affects pine timber and buildings. It was found at first time in 2004 in Western Australia, and has been spreading throughout Perth County ever since.


In order to prevent its spread in the construction area, research and analyse has been made with detailed mapping of its presence and the control measures necessary to prevent its presence.

    Awards and recognitions

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