PFAS
PFAS (per- and poly-fluoroalkyl substances) are a family of manufactured chemicals that do not occur naturally in the environment. PFAS have been used widely in industrial and consumer products since the 1950s to make products which resist heat, stains, grease and water. PFOS (perfluorooctane sulfonic acid), PFHxS (perfluorohexane sulfonic acid), PFOA (perfluorooctanoic acid) and PFBS (perfluorobutane sulfonic acid) belong to this group of chemicals.
PFAS and drinking water
The Australian Drinking Water Guidelines (ADWG), developed by the National Health and Medical Research Centre (NHMRC), provide guidance to water regulators and suppliers on monitoring and managing the quality of drinking water supplied to customers. The ADWG include health-protective guideline values for a wide range of water quality parameters, including PFAS.
The ADWGs are maintained through a rolling review process led by NHMRC. This approach ensures the guidelines remain current by incorporating the latest scientific evidence, technological advancements, and public health considerations. In June 2025, the NHMRC published an update to the ADWG, including new health-based guideline values for the four PFAS compounds shown in Table 1.
Compound | Health-based Guideline Value |
PFOS | 0.008 µg/L |
PFHxS | 0.03 µg/L |
PFOA | 0.2 µg/L |
PFBS | 1 µg/L |
Hunter Water routinely samples for PFAS in the drinking water supplied to all of our drinking water supply zones. Our independent laboratory reports detections over 0.002 micrograms per litre (µg/L), which provides sufficient resolution to ensure our water quality aligns with the ADWGs . We notify NSW Health of any exceedance of ADWG health-based guideline values for PFAS in water we supply to customers. We also regularly publish a summary of results on our website and review PFAS results from across our drinking water system with NSW Health each quarter. Our comprehensive monitoring program demonstrates that the water we supply to customers is safe, and meets the ADWG health-based guideline values for PFAS.
PFAS contamination in Hunter Water catchments
Historic use of PFAS in fire-fighting foams and other products has unfortunately led to numerous instances of contamination in water supply catchments across Australia, including here in the Hunter. The most well-known contamination in this region is associated with historic use of fire-fighting foam at RAAF Williamtown. It is also known that PFAS based foam was used to manage the risk of fire at a fuel-tanker roll-over in Medowie in February 1994.
Based on sampling of raw water quality from all of our raw water sources, we know that PFAS levels are consistently below the limit of reporting in Chichester Dam and Grahamstown Dam, which supply water to Dungog and Grahamstown Water Treatment Plants, at the river offtakes from the Paterson River and Allyn River that supply water to Gresford Water Treatment Plant, in the raw water that is supplied from the Anna Bay Sandbeds to the Nelson Bay and Anna Bay Water Treatment Plants, and in the raw water that is supplied from the eastern end of the Tomago Sandbeds to Lemon Tree Passage Water Treatment Plant.
The only location where we consistently detect PFAS is in the raw water that comes from parts of the Tomago Sandbeds and is supplied towards Grahamstown Water Treatment Plant when the borefield is being operated. Some of this contamination is attributable to past fire-fighting activities at RAAF Williamtown, but the sources at other locations remain unknown.
Hunter Water manages the quality of water supplied from the Tomago Borefield through selective use of borelines to ensure PFAS remains below the drinking water guideline values in water supplied to Grahamstown Water Treatment Plant. Hunter Water’s management of the Tomago Borefield is supported by a comprehensive water quality monitoring program that provides up-to-date information regarding the level of contamination at all borelines when they are operated. Hunter Water’s management of the Tomago Borefield includes isolation of borelines when required to protect against the risk of drawing poor quality water from known areas of groundwater contamination.
Although Grahamstown Dam is only a few kilometres away from the PFAS contamination at Williamtown, it is impossible for water to enter Grahamstown Dam from this plume due to the direction of surface and groundwater flows in the area. Water would need to flow uphill to enter the dam, even in wet conditions. This assessment is based on decades of ongoing hydrological testing and modelling.
PFAS contamination is not uncommon and needs to be managed by every water utility around Australia and the world.
Frequently Asked Questions
-
What are PFAS?
Per-and poly-fluoroalkyl substances (PFAS) are a class of manufactured chemicals with hundreds of manufacturing and industrial applications. PFAS resists degradation in the environment and can bioaccumulate, meaning its concentration increases over time in humans and animals. PFAS chemicals are ‘emerging contaminants’ and there is some evidence they may be harmful to human health. PFAS chemicals include perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS).
-
What is PFAS used for?
PFAS chemicals have been widely used to make everyday products stain-resistant, waterproof and/or nonstick. For example, PFAS has been used in the manufacture of products that:
- Keep food from sticking to cookware
- Make upholstered furniture, carpets and clothing resistant to soil, stains and water
- Make shoes, clothes and mattresses water resistant
- Keep food packaging from sticking to food
- Help fight fires at airfields and other places where petroleum-product-based fires are a risk.
PFOS was also a component of the Scotchgard™ range of products and an ingredient of some industrial additives, as well as Aqueous Film Forming fire-fighting Foams (AFFF™) and Alcohol-Type Concentrate (ATC™) fire-fighting foams for extinguishing flammable fuel fires.
Consumer products made with fluoropolymers and fluorinated telomers, including Teflon® and other trademark products may contain trace amounts of PFOA and other related PFAS as impurities.
-
What is Hunter Water doing to ensure its water supply is safe from contamination
Hunter Water has an extensive ‘catchment to tap’ water quality monitoring program in place as part of our Drinking Water Quality Management System. We routinely test for a wide range of physical, chemical and biological characteristics at all stages of the supply system.
In addition, we test for PFAS including PFOS, PFOA and PFHxS, at all six of our drinking water treatment plants, at Campvale Canal and at 74 locations across our drinking water network.
In the event the Tomago Borefield is operated, a monitoring program is initiated which tests sections of the Borefield prior to connection to the system, and assurance testing is regularly carried out during periods of operation. Any decision to use the Tomago Sandbeds as a drinking water supply is made in consultation and to the satisfaction of NSW Health.
The monitoring and assurance regime has been reviewed to the satisfaction of NSW Health, and any decision to use the Tomago Sandbeds as a drinking water supply is made in consultation with NSW health.
-
Is Hunter Water's drinking water at risk from PFAS contamination spreading from the RAAF base at Williamtown?
No. Although Grahamstown Dam is only a few kilometres away from RAAF Base Williamtown, the source of a local PFAS contamination plume, it is impossible for water to enter Grahamstown Dam from the RAAF Base due to the direction of surface and groundwater flows in the area. Water would need to flow uphill to enter the dam, even in wet conditions. This assessment is based on decades of ongoing hydrological testing and modelling.
Hunter Water has embargoed, or isolated, two of its bore stations that are located in the Williamtown Management Area as a precaution while further investigations are undertaken. It is possible that some or all of these bore stations may be able to supply safe drinking water again in the future if appropriate management strategies can be implemented. The Sandbeds are used as a backup water source, and the water is tested for contaminants, including PFAS, before it enters the drinking water supply. Hunter Water can choose which bores are used and which are not when drawing water from the Sandbeds.
-
Is the water at the Tomago Sandbeds contaminated?
The Tomago Sandbeds are a safe and reliable back up water supply for the Lower Hunter. They can be operated during times of shortfall and provide 20 per cent of the region’s drinking water.
In the event the Tomago Borefield is operated, a monitoring program is initiated which tests sections of the Borefield prior to connection to the system, and assurance testing is regularly carried out during times of operation. Any decision to use the Tomago Sandbeds as a drinking water supply will be made in consultation and to the satisfaction of NSW Health. The monitoring and assurance regime has been endorsed by the NSW PFAS Expert Panel.
Water from the Sandbeds is tested for contaminants including PFAS before it enters the drinking water supply. Hunter Water can choose which bores are used and which are not when drawing water from the Sandbeds.
As previously advised, Hunter Water has embargoed, or isolated, two of its bore stations that are located in the Williamtown Management Area.
-
How widespread is PFAS in the environment?
PFAS is everywhere around the globe due to its widespread manufacturing, processing and use in consumer products. It is widespread in part because the chemicals are persistent in the environment – that is, they resist breaking down when exposed to air, water or sunlight. As a result, people may become exposed to PFAS which was manufactured months or years in the past.
-
Is PFAS in the environment an issue in other parts of Australia?
Due to the extensive use and applications of PFAS chemicals, they are commonly found in the Australian environment including drinking water, surface water, wastewater influent and treated effluent, sediments and house dust. The levels of PFAS in the Hunter region is consistent with other parts of Australia
-
Where does Hunter Water test for PFAS?
Hunter Water undertakes routine sampling and testing for PFAS in:
- The raw water supplied to all Water Treatment Plants
- Drinking water supplied to customers across the Lower Hunter
- Wastewater (sewage) discharged to Hunter Water’s sewerage system by major and moderate trade waste customers
- Raw wastewater, treated effluent and biosolid samples at select wastewater treatment works
Did you know?
We provide safe and reliable drinking water to over half a million customers in the Lower Hunter. The drinking water we supply is routinely tested throughout our water supply systems.
We include PFAS results in our monthly Drinking Water Quality Report. View our monthly report.
From The Newsroom
Hunter Water continues to supply safe drinking water to the Lower Hunter
Hunter Water welcomes the release today by the National Health and Medical Research Council (NHMRC) of the revised Australian Drinking Water Guidelines for PFAS.
A statement from Darren Cleary
Inquiry into PFAS contamination in waterways and drinking water supplies throughout News South Wales – Hunter Water Statement from Darren Cleary.