PFAS

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals. They've been widely used in industrial and consumer products since the 1950s, as they are effective at resisting heat, stains, grease and water.

They can be found in products like stain and water protection for carpets, no-stick cookware, paper coatings, cosmetics and sunscreen. Some PFAS have also been used in fire-fighting foams.

Their resistance to heat, stains, grease and water also means that they don't break down full in the environment, and can travel long distances in water.

With the exception of the Fish River Water Supply System, WaterNSW supplies untreated water, sometimes described as 'raw water' or 'source water', to Sydney Water and councils around NSW who then treat and supply the water to your tap. Learn more about WaterNSW's role.

All water supplied as drinking water must meet the Australian Drinking Water Guidelines. The guidelines specify that:

• For PFOS and PFHxS, the limit is a combined total of less than 0.07 micrograms per litre (µg/L).
• For PFOA, the limit is less than 0.56 µg/L.

PFAS were detected by Sydney Water in the Cascade water filtration plant drinking water supply network. All treated water samples were below these levels, and NSW Health and Sydney Water have confirmed the water supplied from the Cascade water filtration plant to local communities meets the Australian Drinking Water Guidelines and is safe to consume. Learn more about Sydney Water's findings and monitoring.

WaterNSW is conducting additional, targeted PFAS-related investigations to ensure Sydney Water and NSW Health have up-to-date information on the presence of PFAS in the catchment, so any risks continue to be managed appropriately.

The current investigation centers on the Blue Mountains dams. This follows Sydney Water testing, which detected PFAS at levels below the Australian Drinking Water Guidelines in the Cascade water filtration plant supply.

Sydney Water has confirmed the water supplied from the Cascade water filtration plant to local communities is safe to consume and meets the Australian Drinking Water Guidelines.

The Blue Mountains system sources water from within and outside the Blue Mountains catchments. These catchments are a small group of bushland valleys that feed water to Medlow Dam, Greaves Creek Dam and the Upper, Middle and Lower Cascade Dams. The dams are all inaccessible to the public.

These five dams provide water for Sydney Water's Cascade water filtration plant at Katoomba, which supplies drinking water to the middle and upper Blue Mountains.

Supplies can be topped up when needed with water from Oberon Dam via a pipeline from the Fish River Scheme, west of the Great Dividing Range at Oberon.

Water Quality results indicate Medlow Dam being impacted by higher levels of PFAS. Whilst this dam does not supply the water filtration plant directly, this part of the system has been disconnected from supply while further investigations are conducted.

Simplified overview of the Upper Blue Mountains water supply system

Sydney Water PFAS information
View at sydneywater.com.au >

NSW Health PFAS information
View at health.nsw.gov.au >