PFAS
Per and polyfluoroalkyl substances (PFAS) are a large group of manufactured chemicals – more than 4000 – that do not occur naturally in the environment. They have been widely used in products like non-stick cookware, food packaging, textiles, cosmetics, and firefighting foams because of their resistance to heat, stains, grease, and water.
Although not manufactured in Australia, PFAS have been imported directly for use in manufacturing, and indirectly within many industrial and consumer products. Some essential uses of PFAS are still allowed, but due to concerns about their persistence and potential health impacts, efforts are underway in Australia and globally to phase out or ban the most hazardous PFAS.
PFAS stay in the environment for a long time and build up in people and animals. They are now found at low levels in groundwater, surface water and soils in urban areas worldwide. PFAS have been linked to environmental and health risks. Unlike bacteria or viruses that can cause illness quickly, PFAS pose a chronic risk – meaning long-term exposure can lead to health problems. People can be exposed to PFAS through food, consumer products and, to a lesser extent, drinking water.
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 drinking water quality. The ADWG include health-based guideline values for many substances, including PFAS, to ensure water is safe to drink. PFAS was first added to the ADWG in August 2018.
The ADWGs are maintained through a rolling review process led by NHMRC. This approach ensures the guidelines remain current by incorporating the latest science, technology, and public health considerations. In June 2025, the NHMRC published an update to the ADWG, including new guideline values for a selection of PFAS compounds. Table 1 summarises the health guideline values for the four PFAS compounds currently included in the ADWG, which are Perfluorooctanesulfonic acid / perfluorooctane sulfonate (PFOS) Perfluorohexane sulfonate (PFHxS), Perfluorooctanoic acid (PFOA) and Perfluorobutanesulfonate (PFBS).
Compound | Health-based Guideline Value (ug/L) (or ppb) |
PFOS | 0.008 |
PFHxS | 0.03 |
PFOA | 0.2 |
PFBS | 1 |
| Note: 1 microgram per litre (µg/L) = 1 part per billion (ppb). It is important to note that the ADWG guideline values:
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For more information see the ADWG, the NSW Health website, or the Water Services Association of Australia Fact Sheet.
Hunter Water’s Drinking Water PFAS Management Approach
Hunter Water’s approach to managing PFAS in drinking water is underpinned by careful source selection to ensure all water supplied to customers meets the performance standard set by the ADWG. We aim to minimise the concentration of PFAS in water supplied to customers, while balancing the need to manage water quality with maintaining a reliable water supply, including during periods of drought, noting that there are times when operation of the Tomago Borefield cannot be avoided without compromising Hunter Water’s ability to manage drought and other risks. Operation of the Tomago Borefield, when required, is done using a conservative boreline blending and isolation approach to ensure acceptable raw water quality entering Grahamstown Water Treatment Plant (WTP), and ensure that Hunter Water’s operations do not adversely impact the location and trajectory of PFAS contaminant plumes present in groundwater.
Hunter Water’s comprehensive water quality monitoring program includes routine quarterly monitoring of water quality at 83 customer taps throughout the distribution system to demonstrate that the water we supply to customers is safe, and meets the ADWG health-based guideline values for a range of water quality parameters, including PFOS, PFHxS, PFOA and PFBS. In addition, we routinely monitor these compounds in treated water produced at our WTPs, raw water supplied to our WTPs, and further upstream in our drinking water catchments and storages.
We utilise the services of an independent National Association of Testing Authorities (NATA) accredited laboratory for routine water quality sampling and analysis, including scheduled sampling and any ad-hoc or investigation-based PFAS analysis for the drinking water system. Robust sampling, analysis (testing), quality assurance (QA) and quality control (QC) procedures are in place to ensure monitoring data is reliable.
Hunter Water’s routine PFAS samples are analysed for a suite of 28 PFAS compounds including PFOS, PFHxS, PFOA and PFBS. The limit of reporting (LoR) is the lowest concentration of a substance a laboratory can reliably quantify (measure accurately with confidence and precision) in a sample. The 28 PFAS suite used for Hunter Water’s routine PFAS samples currently has a LoR of 0.002 µg/L for PFOS, PFHxS, PFOA and PFBS, which enables us to monitor our performance against the performance standard for these compounds set by the ADWG.
We notify NSW Health of any exceedance of ADWG health-based guideline values, including PFAS, in water we supply to customers. We also publish monthly water quality summary reports on our website and review PFAS results from across our drinking water system with NSW Health each quarter.
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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 the Campvale Canal catchment 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 locations where PFAS is consistently detected is in the raw water from a number of borelines in the Tomago Sandbeds. 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.
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 Williamtown due to the direction of surface and groundwater flows in the area. Decades of groundwater level monitoring, as well as numerical models of the groundwater system, indicate that water from the contaminated areas at Williamtown always flows away from Grahamstown Dam and towards the Tilligerry Creek and Fullerton Cove drainage networks.
PFAS contamination is not uncommon and needs to be managed by every water utility around Australia and the world.
Frequently Asked Questions
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What are PFAS?
Per-and poly-fluoroalkyl substances (PFAS) are a class of manufactured chemicals with hundreds of manufacturing and industrial applications. PFAS compounds resist degradation in the environment and can bioaccumulate, meaning their concentration increases over time in humans and animals. PFAS chemicals include PFOS (perfluorooctane sulfonic acid), PFHxS (perfluorohexane sulfonic acid), PFOA (perfluorooctanoic acid) and PFBS (perfluorobutane sulfonic acid).
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What is PFAS used for?
PFAS chemicals have been widely used to make everyday products stain-resistant, waterproof and/or nonstick. For example, PFAS have 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.
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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 83 locations across our drinking water network. Our monthly water quality summary reports can be found here.
In the event the Tomago Borefield is operated, a monitoring and assurance program developed in consultation with NSW Health is used to manage PFAS risk. The monitoring and assurance regime has been developed in consultation with NSW Health.
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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.
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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 are made in consultation with NSW Health.
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.
In consultation with NSW Health, Hunter Water has previously embargoed, or isolated, two of its bore stations that were deemed to present an unacceptable risk to water supply. Station 7 has been embargoed since 2018 as a precautionary measure, as it is located within the RAAF Base area of operations and in relatively close proximity to the known PFAS contaminated area. Station 9, which is located within a PFAS plume and the EPA defined Secondary Management Zone, has been embargoed since 2015 due to the concentration of PFAS in the area.
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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.
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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
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Where does Hunter Water test for PFAS?
Hunter Water undertakes routine sampling and testing for PFAS in:
- Drinking water supplied to customers across the Lower Hunter
- Treated water produced at all Water Treatment Plants
- Raw water supplied to all Water Treatment Plants
- Selected source waters upstream in the drinking water catchments and storages, including Chichester and Grahamstown Dams, Tomago Sandbeds, Balickera Canal, and Campvale Canal
- Wastewater (sewage) discharged to Hunter Water’s sewerage system by major and moderate trade waste customers
- Raw wastewater, treated effluent and biosolids 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.