Your drinking water is safe to drink and does not require additional treatment. We're committed to providing safe drinking water by adhering to the Australian Drinking Water Guidelines. Our ongoing monitoring confirms that the drinking water produced at all 9 of our water filtration plants meets the Guidelines.
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Safe drinking water is important to everyone
We're continuously reviewing and improving our practices around perfluoroalkyl and polyfluoroalkyl substances (PFAS) and drinking water.
Delivering on our customers' top priorities
Water quality scientist at our West Ryde Laboratory
Since 2022, we have directly connected with more than 13,000 customers through our customer engagement initiatives to ensure we're delivering on our customers' priorities. What we heard was clear: our customers want safe, clean, reliable drinking water every day.
We continuously review and improve our practices. We closely monitor science and research to ensure we identify new hazards and stay ahead of any potential risks. As we learn more, we may adapt our practices.
The quality of our drinking water is closely monitored by qualified scientists and highly trained specialists in our National Association of Testing Authorities (NATA) certified state-of-the-art laboratories. We test the drinking water produced by our water filtration plants for PFAS and publish the latest results as part of our commitment to water quality.
We use the most advanced research and testing methods to detect and measure trace amounts of substances like PFAS. In fact, we conduct our tests so stringently that they pick up PFAS levels that are almost undetectable, and significantly lower than what is regulated. We test the drinking water produced by our water filtration plants for PFAS and publish the latest results as part of our commitment to water quality.
Understanding PFAS
PFAS are man-made chemicals found in many everyday products. They've been widely used in many industrial and consumer applications as they're effective at resisting heat, stains, grease and water.
PFAS have been used in some common consumer products, including but not limited to:
- firefighting foams
- non-stick cookware like Teflon
- waterproof clothing
- cosmetics and sunscreen
- food packaging, such as grease-resistant wrappers and takeaway coffee cups
- stain-resistant carpets and upholstery.
What is unique about PFAS?
The properties that make PFAS useful in industrial and consumer products can also make them problematic in the environment. PFAS don't break down readily and they're highly mobile in water. This means they travel long distances from their source, and don't break down fully in the environment. Australia, which hasn't manufactured PFAS, has a significantly lower level and spread of PFAS contamination than other countries like the United States.
Government response to PFAS
From 1 July 2025, the Australian Government is banning the manufacture, import, export or use of PFOS, PFOA and perfluorohexane sulfonate (PFHxS), and any products that contain them.
The NSW Government is coordinating a multi-agency response to PFAS, informed by the best science and evidence. The government is committed to transparency, ensuring the community has access to up-to-date information and supporting water utilities to deliver safe drinking water. Find out more at PFAS and drinking water – information and updates.
Setting the standards for safe drinking water
To ensure the safety of drinking water and to provide a basis for determining the quality of water supplied to consumers throughout Australia, the National Health and Medical Research Council (NHMRC) developed the Australian Drinking Water Guidelines. The Guidelines undergo rolling revisions to ensure they represent the latest available scientific evidence on safe drinking water. They're used by state and territory health departments, drinking water regulators, local health authorities and water utilities like us.
The Guidelines and PFAS values
In 2018, for the first time, the Guidelines included maximum health-based values for perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) in drinking water. The values were derived using tolerable daily intake (TDI) values recommended by the Australian Department of Health and Aged Care. In June 2025, the NHMRC added perfluorobutanesulfonic acid (PFBS). It now recommends new lower PFAS values for drinking water.
The latest PFAS values are expressed in nanograms per litre. One nanogram per litre (ng/L), or one thousandth of a microgram per litre (µg/L), is the same as one part per trillion (ppt). This is the equivalent of one drop in 20 Olympic-sized swimming pools.
We can confirm that our 9 water filtration plants are supplying drinking water below the Guideline PFAS values.
Maximum values for PFAS chemicals
There are many types of PFAS. The Australian Drinking Water Guidelines specify limits for PFOS, PFHxS, PFOA and PFBS.
| Type of PFAS | Value in Australian Drinking Water Guidelines |
|---|---|
PFOS |
8 ng/L (less than 0.008 µg per litre) |
PFHxS |
30 ng/L (less than 0.03 µg per litre) |
PFOA |
200 ng/L (less than 0.2 µg per litre) |
PFBS |
1,000 ng/L (less than 1.0 µg per litre) |
The Water Services Association of Australia provides a detailed PFAS fact sheet that outlines the process of Guideline development in the Australian context.
The Guideline PFAS values have been calculated for a lifetime of exposure. There's more information on how the values are worked out in the NHMRC Review of PFAS in Australian drinking water.
Treated water vs untreated water
It's important to know that the Australian Drinking Water Guidelines only apply to treated water. This is the water we supply to you. We ensure that all your treated drinking water meets the Guidelines, and we report our ongoing PFAS monitoring results for treated water.
The water found in dams and other catchments is untreated water. Untreated water, or raw water, is managed by WaterNSW and is not subject to the Australian Drinking Water Guidelines. WaterNSW conducts ongoing PFAS monitoring of the Blue Mountains and Greater Sydney catchments and publishes PFAS results for untreated water on its website. WaterNSW has released its initial investigation into the source of PFAS contamination in the Blue Mountains catchment. Find out more about its Blue Mountains PFAS investigation.
Blue Mountains drinking water supply
We've been working to lower PFAS levels in the Blue Mountains. Greaves Creek and Medlow dams remain isolated from the supply while WaterNSW completes detailed site investigations into the source of elevated PFAS levels in the Blue Mountains catchment area. You can read about the Blue Mountains PFAS investigation.
Cascade Water Filtration Plant
We began testing treated water at the Cascade Water Filtration Plant in June 2024, with weekly testing starting on 3 October 2024. Our water systems are dynamic. Residents in the Blue Mountains may receive water from either the Cascade or Orchard Hills water filtration plant. The interconnection between the Cascade and Orchard Hills systems varies depending on operational needs and storage capacity.
Purpose-built treatment system
A treatment system specifically to remove PFAS has been operating at the Cascade plant since December 2024. We wanted to ensure the plant was well equipped to meet the Guidelines' lower PFAS values.
The $3.4 million treatment system uses granular activated carbon (GAC) and ion exchange resin to remove PFAS. Sample results indicate that PFAS levels for treated water in the Cascade drinking water system have decreased.
PFAS treatment system at the Cascade Water Filtration Plant
Repeat monitoring samples for Jamieson and Shipley Reservoirs
The Blue Mountains water network is complex and covers a large area. To ensure that water from the Cascade Water Filtration Plant reaches the entire network, we've started additional monitoring.
In April 2025, we conducted a more detailed and targeted PFAS monitoring program across locations in the Blue Mountains as part of our commitment to water quality.
Jamieson and Shipley Reservoirs, which are only used intermittently and provide very limited supply to customers, returned results that met all current Guideline PFAS values. However, results exceeded the proposed new Guideline value for PFOS.
Best practice is to repeat a sample if a test result is not typical, so we collected repeat samples. The PFOS result for Shipley Reservoir was slightly lower than the first sample. The PFOS result for Jamieson Reservoir was higher than the first sample. It's not unusual to have some variability between sample results.
To address customer and community concerns, we've isolated both reservoirs from the network while we clean and perform maintenance. As part of this process, we will also test any sediment removed. It will then be classified according to the NSW Environmental Protection Authority (EPA) waste classification and disposed of accordingly.
Test results for the Blue Mountains water supply network (28 KB, XLSX) were taken on 7 and 15 April 2025.
North Richmond Water Filtration Plant
In 2018, the community raised concerns that PFAS from the Royal Australian Air Force (RAAF) Base Richmond could contaminate drinking water. In 2019, we undertook a targeted monitoring program to assess the potential for this to be the case. Our North Richmond Water Filtration Plant sources raw water from the Hawkesbury-Nepean River 13 kilometres upstream of where the water from the RAAF drains into the river. Therefore, low readings were consistent with expectations.
Following the 2019 study, we conducted an annual monitoring program for the North Richmond plant. This commenced in November 2023. Since October 2023, we've conducted weekly testing of treated water at the plant. See our ongoing PFAS monitoring results.
FAQs
Yes. We're committed to transparency and maintaining public trust. That's why we routinely publish PFAS test results for drinking water supplies across Greater Sydney, including the Blue Mountains. We publish these PFAS monitoring results weekly. PFAS levels are consistently below the Australian Drinking Water Guidelines.
We supply around 1.5 billion litres of safe drinking water to customers each day. Most of our water is sourced from a network of catchments and dams managed by WaterNSW. WaterNSW is responsible for taking care of the state's water at the source. It conducts ongoing PFAS monitoring of the Blue Mountains and Greater Sydney catchments and publishes PFAS results on its website.
Our ongoing PFAS monitoring confirms that the drinking water produced at all 9 of our water filtration plants meets the Australian Drinking Water Guidelines developed by the NHMRC and supported by NSW Health.
The most effective way to limit PFAS in drinking water is to identify potential sources of contamination in drinking water catchments and then work with relevant stakeholders to implement effective control measures.
Some treatment processes such as reverse osmosis can remove PFAS, but they're expensive and highly energy consuming. A significant body of research is being carried out globally on how to treat PFAS contamination.
The PFAS treatment system at the Cascade Water Filtration Plant uses granular activated carbon (GAC) and ion exchange resin to reduce PFAS to very low levels. Water produced at the plant meets current and proposed Australian Drinking Water Guidelines.