PFAS NEMP 3.1 released: updated PFOS and drinking water guideline values reshape contaminated site obligations in Australia
Overview
The Heads of EPA Australia and New Zealand (HEPA) formally released Version 3.1 of the PFAS National Environmental Management Plan (PFAS NEMP 3.1) on 2 June 2026. The South Australian EPA and the Commonwealth Department of Climate Change, Energy, the Environment and Water (DCCEEW) both published updated regulatory overviews in mid-June 2026, confirming adoption of the revised framework. This update is the most consequential revision to PFAS screening criteria in several years, and its effects will be felt immediately across contaminated site investigations, risk assessments, remediation designs, and property transactions throughout Australia.
PFAS NEMP 3.1 incorporates two major external guideline updates: the June 2025 revised Australian Drinking Water Guidelines (ADWG) health-based values derived by the National Health and Medical Research Council (NHMRC), and the March 2026 Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZG) default guideline values (DGVs) for perfluorooctane sulfonate (PFOS) in freshwater and marine environments. The integration of both updates into a single revised NEMP creates a unified, nationally consistent screening framework that practitioners and regulators are expected to apply immediately.
The revision pulls in two directions simultaneously. The default guideline value for PFOS in freshwater ecosystems has increased substantially, reducing the frequency of exceedances where direct aquatic exposure is the primary concern. At the same time, the drinking water guideline values for PFOS, PFOA, and PFHxS have all been reduced significantly, meaning groundwater plumes that previously sat below screening thresholds may now exceed the new limits. For developers, landowners, lenders, and councils with known or suspected PFAS-impacted sites, the practical consequence is straightforward: site files that were closed or classified as low-risk under NEMP 3.0 criteria may need to be reopened and reassessed.
Key details of the PFAS NEMP 3.1 guideline changes
The most discussed change in PFAS NEMP 3.1 is the revision to the PFOS default guideline value for freshwater aquatic ecosystems at the 99% species protection level. The new DGV is 0.02 µg/L (20 ng/L), replacing the highly conservative interim DGV of 0.00023 µg/L (0.23 ng/L) that applied under NEMP 3.0. This represents an approximately 87-fold increase in the threshold and reflects a substantially expanded ecotoxicological dataset covering 37 aquatic species. The previous interim value was always acknowledged as provisional due to data limitations; the 2026 ANZG revision provides a far more statistically defensible basis for the DGV and is expected to reduce the incidence of investigation triggers driven solely by direct aquatic exposure concerns.
However, the relaxation of the direct-exposure DGV does not simplify ecological risk assessment for all sites. PFAS NEMP 3.1 formally introduces a new biota screening threshold for PFOS in freshwater set at 0.0005 µg/L (0.5 ng/L). This threshold specifically addresses bioaccumulation and biomagnification pathways, recognising that mammals and birds that consume aquatic organisms can accumulate PFOS at concentrations far exceeding those predicted by direct water-quality guidelines alone. Where measured water concentrations exceed 0.5 ng/L, practitioners are now required to conduct tissue sampling of aquatic fauna to assess risks to predatory wildlife receptors. This represents a new and distinct investigation requirement that did not formally exist under NEMP 3.0, and it will add complexity and cost to ecological risk assessments at sites adjacent to wetlands, rivers, and estuaries.
The drinking water guideline changes are the most immediately significant for the majority of contaminated land projects. The NHMRC-derived ADWG health-based values now embedded in PFAS NEMP 3.1 are as follows. For PFOS, the new guideline is 0.008 µg/L (8 ng/L), reduced from the previous 0.07 µg/L (70 ng/L), representing an eightfold reduction. For PFOA, the new guideline is 0.2 µg/L (200 ng/L), down from 0.56 µg/L (560 ng/L), approximately a threefold reduction. For PFHxS, the new guideline is 0.03 µg/L (30 ng/L), down from 0.07 µg/L (70 ng/L), more than a twofold reduction. PFBS now has a formal guideline limit for the first time, set at 1.0 µg/L (1,000 ng/L). Recreational water guidelines have also been updated to align with the new drinking water values.
The laboratory detection limit implications of these changes deserve specific attention. At 8 ng/L for PFOS, many standard PFAS analytical methods operating at reporting limits of 2 ng/L to 5 ng/L per compound will still be capable of resolving exceedances, but the margin between a clean result and an exceedance is now extremely narrow. Practitioners using older analytical packages with higher reporting limits, particularly those negotiated under pre-2023 laboratory contracts, may find that their current detection capability is insufficient to confirm compliance against the new PFOS drinking water guideline. Method 533 and EPA Method 537.1 (or their Australian laboratory equivalents) with sub-2 ng/L reporting limits per compound will generally be required for any groundwater programme where drinking water use is a plausible receptor pathway.
Australian context: how PFAS NEMP 3.1 interacts with state and territory regulatory frameworks
PFAS NEMP 3.1 operates as a nationally agreed framework rather than a directly enforceable instrument, but its practical regulatory weight comes from its adoption by state and territory EPAs, which incorporate its screening values into their investigation and notification triggers. In South Australia, groundwater concentrations that exceed PFAS NEMP guideline values trigger mandatory notification obligations to the EPA and may require the site to be listed on the Environmental Register, with subsequent remediation or management requirements determined on a site-by-site basis.
References and related sources
- Primary source: www.epa.sa.gov.au
- enviliance.com
- pjra.com.au
- fasttrack.govt.nz
- oup.com
- PFAS National Environmental Management Plan (NEMP)
- NEPM Assessment of Site Contamination
- ANZG Water Quality Guidelines
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This is an iEnvi Machete news summary. Prepared by iEnvi to summarise the source article for contaminated land, groundwater, remediation, approvals and site risk professionals.
Published: 18 Jun 2026
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