PFAS or “Forever Chemicals”: What We Know, What We Don't, and How to Remove Them

"Forever chemicals" have been all over the news lately, and if you've found yourself wondering whether that headline applies to the water coming out of your own tap, you're not alone. PFAS is a confusing topic - partly because it covers thousands of different chemicals, and partly because the honest answer is "it depends on your water source and where you live."

Here's what's we know about PFAS in New Zealand and Australian water, where uncertainty lies, and which home filtration methods are backed by evidence.

What Are PFAS?

PFAS stands for per- and polyfluoroalkyl substances - a family of synthetic chemicals that includes well-known variants like PFOA and PFOS. They were widely used from the mid-20th century onward in firefighting foam, stain-resistant fabric, and non-stick cookware, and they've earned the "forever chemicals" nickname because they break down so slowly in the environment. Estimates of exactly how many PFAS compounds exist vary a lot depending on the definition used - from around 4,700 in the original OECD inventory to more than 10,000 under broader definitions used elsewhere [10].

What We Know: How PFAS Is Regulated

New Zealand

Taumata Arowai, New Zealand's drinking water regulator, sets Maximum Acceptable Values (MAVs) for PFAS in the Drinking Water Standards.

 Two limits currently apply:

1.        A combined MAV of 70 ng/L for PFOS and PFHxS together

2.        A separate MAV of 560 ng/L for PFOA [1][3].

These were set in 2022, based on guideline values New Zealand aligned to back in 2018 - at the time, in step with Australia's guidelines of the day [2].

Recent testing is genuinely reassuring for most people on council-supplied water: testing across 20 NZ suburbs found PFAS at very low levels, generally under 1 part per trillion [2]. That said, it isn't uniform. Auckland's Onehunga water treatment plant was taken offline in 2022 over concerns of PFAS levels, and it's not expected to reopen until 2029, following a $40 million upgrade to add granular activated carbon filtration. A 2023 national groundwater survey also found a handful of sites - mostly near historical firefighting-foam use, such as around Ohakea Air Force Base - where PFAS levels exceeded the MAV [8].

Taumata Arowai has said there are currently no plans to revise New Zealand's limits, even though both Australia and the United States have moved to considerably stricter thresholds since 2018 [2].

Australia

In Australia, the National Health and Medical Research Council (NHMRC) sets the health-based guideline values in the Australian Drinking Water Guidelines (ADWG), which state and territory regulators then use to set enforceable limits for water suppliers [4].

Until mid-2025, Australia's guideline values were the same ones New Zealand still uses today. In June 2025, the NHMRC substantially tightened them following a multi-year scientific review:

1.        PFOS dropped to 8 ng/L

2.        PFOA to 200 ng/L

3.        PFHxS was split out as its own limit at 30 ng/L

4.        PFBS was set at 1000 ng/L [4][5].

The NHMRC has stated that the large majority of Australia's water supply already sits below these newer, stricter values [4]. States and territories are still working through timelines to fully implement them.

As in New Zealand, the exceptions tend to cluster around specific contamination sources rather than general supply. The best-documented case is the area around RAAF Base Williamtown in NSW, where historical firefighting-foam use contaminated groundwater and private bores from the 1970s onward. The local water utility, Hunter Water, manages this by selectively drawing from unaffected bores to keep the treated supply under guideline levels [6][7].

The pattern is similar in both countries: council or utility-supplied water is generally in good shape  - but that reassurance doesn't automatically extend to private bores, tanks, or properties near current or former defence, industrial, or firefighting-training sites. If that's your situation, testing your specific supply is the only way to actually know.

What We Don't Know: The Open Questions

Gaps worth knowing about, on top of the regulatory picture above:

• Most individual PFAS aren't tested for. Regulatory testing in both countries focuses on the handful of compounds with the clearest health data - PFOA, PFOS, PFHxS, and a few others - out of the thousands that exist [1][4][10].
• Private bores and tank supplies aren't routinely monitored. If your household relies on bore, tank, or rural river water - especially near airports, industrial sites, or current or former defence land - that supply generally isn't covered by council or utility testing in either country. Whether PFAS is present is genuinely unknown unless you test it yourself.
• The toxicology is still being refined. As an example of how the science keeps moving: in 2023, the International Agency for Research on Cancer (IARC, part of the WHO) classified PFOA as carcinogenic to humans and PFOS as possibly carcinogenic to humans, based on a review of animal and mechanistic evidence [9]. Classifications and guideline values for individual PFAS compounds have shifted more than once in the past decade, and will likely keep evolving.

If you're on a private supply and this is on your mind, testing is the only way to actually answer the question.

What Actually Removes PFAS

Three approaches have real evidence behind them, though they're not all practical for a typical home setup:

• Reverse osmosis (RO). This is the most effective residential option. RO pushes water through a semi-permeable membrane fine enough to reject the large majority of PFAS molecules. Peer-reviewed studies put long-chain PFAS (like PFOA and PFOS) rejection at 90–99%; shorter-chain PFAS are somewhat harder to remove but are still substantially reduced [12]. 
• Advanced carbon block filtration. Not every carbon filter qualifies - a basic pitcher filter isn't built for this. Systems using dense, multi-stage carbon block media, certified to NSF/ANSI 53, carry the same PFAS-reduction testing as RO systems, generally with somewhat more variable results depending on water chemistry and filter life [11].
• Ion exchange resin. Anion exchange media is also covered under NSF/ANSI 53 and can be particularly effective against shorter-chain PFAS, but it's mostly deployed in specialised or commercial-scale systems rather than typical household filters [11].

Still not sure what's actually in your water?

Testing your water can give you the answer. If you're on tank, bore, or rural supply, request a Water Testing Kit - a couple of quick details and we'll be in touch with next steps. And if you want the strongest layer of protection regardless of supply type, browse our reverse osmosis systems - the one filtration method with the evidence to back a PFAS-reduction claim. Not sure which makes sense for your household? Get in touch and we'll walk you through it.

Sources

1. Water Services (Drinking Water Standards for New Zealand) Regulations 2022 — legislation.govt.nz
2. RNZ, "Australia, US slash limits on 'forever chemicals' in drinking water, but NZ staying put" — rnz.co.nz
3. Water New Zealand, "The Changing Landscape of 'Forever Chemicals'" — waternz.org.nz
4. NHMRC, "Updated Australian Drinking Water Guidelines" (June 2025) — nhmrc.gov.au
5. NHMRC, Australian Drinking Water Guidelines — PFAS values (Part 5) — guidelines.nhmrc.gov.au
6. Hunter Water, "PFAS" (Tomago bore management) — hunterwater.com.au
7. NSW EPA, RAAF Base Williamtown PFAS investigation — epa.nsw.gov.au
8. New Zealand EPA, "National Survey of PFAS in Groundwater" (May 2023) — epa.govt.nz
9. IARC/WHO, carcinogenicity classification of PFOA and PFOS (Dec 2023) — iarc.who.int
10. UNEP, "Per- and Polyfluoroalkyl Substances (PFASs)" — unep.org
11. NSF, "PFOA/PFOS Reduction Claims Requirements Added to NSF Standards" — nsf.org
12. ScienceDirect, review of NF/RO membrane PFAS removal — sciencedirect.com
13. Culligan, "Does boiling water remove PFAS?" — culligan.com