Updated Australian Drinking Water Guidelines

NHMRC has published updated advice on per- and polyfluoroalkyl substances (PFAS) in the Australian Drinking Water Guidelines (the Guidelines).

PFAS are human made chemicals that make products resistant to heat, stains, grease, and water. Because of their widespread use, almost everyone will have some exposure to PFAS in their lifetime. 

The Guidelines include revised health-based guideline values for:

• perfluorooctane sulfonic acid (PFOS) – 8 nanograms per litre
• perfluorooctanoic acid (PFOA) – 200 nanograms per litre
• perfluorohexane sulfonic acid (PFHxS) – 30 nanograms per litre
• perfluorobutane sulfonic acid (PFBS) – 1000 nanograms per litre.

The final values are the same as those proposed at public consultation, except for PFOS where the final guideline value has been revised from 4 ng/L to 8 ng/L. This is based on the selection of a more robust benchmark dose model advised by NHMRC’s Water Quality Advisory Committee, following consultation comments. By comparison, the previous value was 70 ng/L (shared with PFHxS).

This update is the result of a comprehensive review of the latest scientific evidence on PFAS in drinking water for the Australian context, including both national and international scientific reviews. Comments received during the public consultation conducted in October 2024 have been carefully considered, and a further round of expert review and targeted consultation undertaken.

The Guidelines are used by States and Territories to regulate safe drinking water. Jurisdictions will now determine the timelines for which water providers will be expected to meet the new values.

Depending on the jurisdiction, states and territories or water suppliers are responsible for determining how often water supplies are tested. These decisions are based on water catchment risk assessments, informed by water testing data.

As it stands, the health risks from PFAS in drinking water is low for most Australians. The information available shows that most water supplies are already below the new, lower guideline values, and these values are based on minimising risk over a lifetime’s worth of exposure. NHMRC uses conservative assumptions in setting these values, and drinking water is only one of many sources of possible PFAS exposure.

NHMRC is responsible for producing the Guidelines to ensure a consistent and robust approach to protecting public health across the country. The Guidelines provide an authoritative reference to the Australian community, state and territory water regulators and water suppliers on what defines safe, good quality drinking water, how it can be achieved, and how it can be assured.

For further information, visit the NHMRC Review of PFAS in Australian drinking water webpage.

Quotes attributable to NHMRC CEO, Professor Steve Wesselingh:

• “This work has been informed by a rigorous evidence review supported by independent expert review, targeted and public consultations, and we are grateful for the valuable input received through public consultation last year.
• “These final guideline values, including the PFOS guideline value, have been reviewed and supported by our expert advisory committee, an independent expert review, jurisdictional public health experts including the Chief Health Officers, and have been supported by the Council of NHMRC.
• “Since we put out our draft PFAS values in October, we’ve seen many water suppliers test their sources to provide greater reassurance to the public that their drinking water is safe.
• “It is critical to note that the vast majority of our national water supply is below this guidance even though we’ve taken a conservative approach and used cautious assumptions in setting the updated PFAS values.
• “PFAS are widely present in many everyday items and drinking water is only one source for possible PFAS exposure, so higher values in drinking water for short periods is unlikely to increase health risks.
• “NHMRC is responsible for developing and updating the Australian Drinking Water Guidelines. These guidelines are used by state and territory health departments, drinking water regulators, local health authorities and water utilities to ensure the safety of drinking water throughout Australia.”