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The drinking water we supply is of excellent quality and we run a comprehensive drinking water quality management program to make sure it remains this way.

We consistently meet water quality health standards set by the Department of Health (DoH).

We are one of Australia’s largest water suppliers delivering more than 387 billion litres of high-quality drinking water from 38 surface water sources, 85 groundwater sources, two major desalination plants and one groundwater replenishment scheme to 1.36 million properties through 35,122 km of water mains.

Managing our drinking water quality

To verify the delivery of safe drinking water and to assess the aesthetic quality of your water, we run an extensive water quality monitoring program. We base our performance on more than 74,500 samples from water sources, treatment plants and pipe networks that supply our customers, with more than 355,000 individual analyses performed by independent laboratories.

We also have a Drinking Water Quality Policy and a Drinking Water Source Protection Policy, which set out our commitments in supplying safe, high quality drinking water to our customers and protecting our water catchments.

In 2022, an independent review of our Drinking Water Quality Management Performance found that:

  1. our internal standards reflect the Australian Drinking Water Guidelines and DoH requirements
  2. our management system is effectively used for managing and reporting in accordance with our internal standards and external reporting requirements
  3. we have effectively managed the Source Protection operation requirements within the catchment areas
  4. our management framework reflects good resourcing of drinking water quality management structure, we have established and maintained procedures that are designed to facilitate compliance with the MoU requirements, we have continually enhanced our reporting mechanisms and we continue to demonstrate a strong commitment to monitoring and achieving compliance with DoH requirements and continued learning and improvement.

What is in our drinking water?


We add chlorine to all our water supply schemes. Chlorine is used as a disinfectant which provides lasting, effective protection from the water treatment plant to your tap. It is especially effective where long pipelines and high water temperatures increase the potential for growth of harmful organisms in our water.


Fluoride is added to some water supply schemes to improve dental health, as directed by the Department of Health (DoH). The use of fluoride is regulated by the Fluoridation of Public Water Supplies Act 1966, and the dose rate is set by a steering committee which reports to the Minister for Health. To determine if your locality receives fluoridated drinking water, please see the Drinking Water Quality Annual Report or the tables below.

For more information about the DoH’s directive on fluoridation, visit the Department of Health’s website or call 08 9222 2000.

Who regulates our drinking water quality?

The DoH regulates drinking water quality in Western Australia. Our Memorandum of Understanding for Drinking Water with DoH enables the department to audit our water quality, management and reporting systems to ensure we consistently comply with Australian Drinking Water Guidelines. Compliance with the Memorandum of Understanding is also a requirement of our Water Services Licence, which is issued by the Economic Regulation Authority.

Schedules 4 to 9 of the Memorandum of Understanding contain lists of substances and materials that may or may not be used in contact with drinking water. These schedules are now available from the Department of Health website.

How do we report on our performance?

Our Drinking Water Quality Annual Report for 2022-23 provides a detailed overview of our water quality performance. We produce this report in line with the requirements of our Water Services Licence, our Memorandum of Understanding for Drinking Water with the Department of Health and the Australian Drinking Water Guidelines.

Water quality data tables by region