Greater Sydney

A precautionary round of recent PFAS testing on the major supply dams for Greater Sydney confirmed PFAS traces in some dams at levels well below those identified in the Blue Mountains.

The results are consistent with those received by Sydney Water and confirm that the Blue Mountains – notably Medlow Dam – remains the priority for the WaterNSW investigation into the presence of PFAS in WaterNSW Greater Sydney dams.

WaterNSW will keep the community informed as the investigation progresses and will work closely with NSW Health and Sydney Water to ensure drinking water remains safe.

Results

These results reflect the untreated, raw source water in WaterNSW’s dams. This water is not supplied directly for use as drinking water, but is supplied to Sydney Water for treatment.

For drinking water results, please visit Sydney Water.

Source water testing location	Date	Depth/location	Perfluorooctanoic acid (PFOA)	Sum of PFHxS and PFOS
			ADWG 0.56µg/L*	ADWG 0.07µg/L*
Cataract Dam	11/09/24	16 m below surface	<0.0005	0.0006
Cordeaux Dam, Cataract	11/09/24	16 m below surface	<0.0005	<0.0003
Nepean Dam, Bargo	11/09/24	20-21 m below surface	<0.0005	<0.0003
Source water inlet to Cascade water filtration plant	10/09/24	Inlet tap	<0.0005	0.0213
Source water inlet to Illawarra water filtration plant, Kembla Grange	11/09/24	Inlet tap	<0.0005	0.0003
Source water inlet to Macarthur water filtration plant, Appin	11/09/24	0 m below surface	<0.0005	0.0003
Source water inlet to Macarthur water filtration plant, Appin	11/09/24	0 m below surface	<0.0005	<0.0003
Source water inlet to Nepean water filtration plant, Bargo	11/09/24	Inlet tap	<0.0005	<0.0003
Source water inlet to Orchard Hills water filtration plant, Orchard Hills	9/09/24	Inlet tap	<0.0005	0.0013
Source water inlet to Prospect water filtration plant, Wetherill Park	9/09/24	Inlet tap	<0.0005	0.0015
Source water inlet to Prospect water filtration plant, Wetherill Park	9/09/24	2 m below surface	<0.0005	0.0004
Source water inlet to Warragamba water filtration plant	9/09/24	Inlet tap	<0.0005	0.0013
Source water inlet to Woronora water filtration plant, Heathcote	11/09/24	Inlet tap	<0.0005	0.0005
Upper Avon Valve Chamber at Avon Dam, Avon	11/09/24	9 m below surface	<0.0005	<0.0003
Upper Cascade Dam	10/09/24	1 m below surface	<0.0005	0.0204
Upper Cascade Dam	10/09/24	6 m below surface	<0.0005	0.0196
Warragamba Dam	10/09/24	45 m below surface	<0.0005	0.0007
Woronora Dam	11/09/24	12 m below surface	<0.0005	0.0005

*Australian Drinking Water Guidelines (ADWG) are listed for reference, but do not apply to source water.

Frequently asked questions

Is Sydney’s water safe to drink?

NSW Health and Sydney Water have confirmed that Sydney’s water is safe to drink.

Learn more about Sydney Water's findings and monitoring.

Water goes through multiple levels of testing to ensure it is safe and meets the Australian Drinking Water Guidelines.

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. The Fish River Water Supply System is an exception. This process of testing and treating the supplied ‘source water’ we supply is rigorous, ensuring that drinking water that comes out of your tap is safe and meets the Australian Drinking Water Guidelines.

How is the Sydney drinking water catchment monitored?

Sydney’s drinking water catchment is 16,000 square kilometres – about half the size of Belgium.

Water quality monitoring across the catchment follows a targeted, risk-based approach to help ensure the treated water supplied for consumption meets the Australian Drinking Water Guidelines. Consistent with the government regulatory frameworks, the approach is based on expert advice from NSW Health and other authorities such as the Environment Protection Authority.

What testing is being done?

WaterNSW conducts routine testing across the Greater Sydney catchment to ensure the best quality water is supplied to Sydney Water, where it is further tested and treated to meet Australian Drinking Water Guidelines. Water goes through multiple levels of testing and treatment to ensure it is safe and meets the Australian Drinking Water Guidelines.

Greater Sydney

Results

Frequently asked questions

Related links