Monitoring for PFAS 

Melbourne Water proactively monitors for per and polyfluoroalkyl substances (PFAS) in our water supply catchments, ensuring the production of safe and secure high-quality drinking water for our customers and communities.

We comply with the Victorian Safe Drinking Water Act 2003 and follow the Australian Drinking Water Guidelines.

We have recently commenced further monitoring for PFAS at several sites located across our protected and open water supply catchments. These samples are analysed by an independent accredited laboratory.

The Australian Drinking Water Guidelines specify safe limits, otherwise known as guideline values, for PFOA (Perfluorooctanoic acid), PFOS (Perfluorooctane sulfonic acid) and PFHxS (Perfluorohexane sulfonic acid).

A 2024 comprehensive monitoring program for our water supply catchments has not detected PFAS. The testing protocols can detect PFAS at levels as low as 2 nanograms per litre. Monitoring results show water from our catchments meets the Australian Drinking Water Guidelines as well as the draft PFAS guidelines under review by the National Health and Medical Research Council.

Further information

What are PFAS (per and polyfluoroalkyl substances)?

PFAS are a group of human-made substances found in many products widely used by consumers and industry since the mid-1900s.

PFAS are often known as ‘forever chemicals’ and are of concern because they can persist for a long time, both in the environment and in humans. 

Laboratories can detect miniscule amounts of PFAS worldwide. PFAS are commonly detected at trace levels in groundwater, surface water and soils worldwide.

What are the Australian Drinking Water Guidelines for PFAS?

Australian Drinking Water Guidelines are set by the National Health and Medical Research Council (NHMRC) and currently include health-based guideline values (limits) for the following three PFAS:

• less than 0.56 micrograms per litre for PFOA
• less than 0.07 micrograms per litre for the sum of PFOS and PFHxS combined.

For comparison, 1 microgram per litre is equivalent to one part per billion.

The NHMRC uses the latest scientific evidence, ensuring that guidelines remain up to date and safe.

What do the proposed changes to the Australian Drinking Water Guidelines for PFAS mean for Melbourne Water?

New draft guideline values (limits) for PFAS have recently been released by the NHMRC for public consultation. We understand the draft update to the Australian Drinking Water Guidelines and the new draft guideline values will be finalised in April 2025.

Melbourne Water welcomes the draft update and we are currently reviewing the proposed changes. Results from our 2024 comprehensive monitoring program are still below the draft PFAS guidelines under review.

How has Melbourne Water previously monitored for PFAS in drinking water?

In the past, we have conducted proactive testing for PFOA, PFOS and PFHxS in open water supply catchments more exposed to urban and agricultural land uses with potential sources of PFAS. Our results from two rounds of historical monitoring (2010–2011 and 2014–2017) showed concentrations of PFOA, PFOS and PFHxS were well below the guideline values (limits) specified in the Australian Drinking Water Guidelines.

What is our current monitoring for PFAS in drinking water?

As part of our periodic review of water quality risks, we commenced further monitoring for PFAS in August 2024.

We are currently monitoring seven sites in our protected and open water supply catchments, including:

• two sites in the Yarra Ranges catchment
• two sites in the Tarago catchment
• one site near Maroondah catchment
• one site in the mid-Yarra catchment
• one site near Yan Yean catchment.

How does the water supply network operate?

Melbourne Water supplies bulk drinking water to several water corporations who supply water directly to customers:

• Metropolitan water corporations - Yarra Valley Water, Greater Western Water and South East Water, and
• Regional water corporations - Barwon Water, Gippsland Water, South Gippsland Water and Westernport Water.

Drinking water is sourced from a combination of protected and open water supply catchments and from seawater desalination. It is then treated before being transferred through Melbourne Water’s drinking water network to the metropolitan and regional water corporations who supply water to customers through their own networks.