A filter certified to reduce PFAS reduces some PFAS, under set laboratory conditions, on a brand new cartridge. That is not the same claim as removing PFAS from your water, though it is usually sold as if it were. The gap between those two statements is wide, and the regulators are far clearer about it than the marketing is.
Quick answer: Certification tests a filter against a handful of named PFAS compounds. It runs on prepared water, at a set flow rate, using a new cartridge. It does not certify that every PFAS is gone, or that the result holds as the media fills up. Meanwhile Australian scheme water is monitored down to one part per trillion.
PFAS are a family of manufactured chemicals, used since the 1950s to make products resist heat, stains, grease and water. They are often called forever chemicals because they break down very slowly. They are also the most oversold claim in water treatment right now, which is the part worth understanding first.
It means the product passed a specific test. It does not mean what most people assume it means.
The certification most filters carry is written by NSF and accredited by ANSI. A laboratory spikes water with particular PFAS compounds at a known strength. It runs that water through a new filter at a set flow rate. Then it measures what comes out the other side. Pass the threshold and the product can carry the claim.
That is a real test and it is worth having. It is just narrower than the words on the box suggest, in three specific ways.
There are thousands of PFAS. Certification tests against a short list of them, historically PFOA and PFOS above all. The US Environmental Protection Agency puts it carefully. Some filters, it says, “have been certified to remove some PFAS chemicals”. Some, not all.
The EPA then gives buyers an instruction that tells you everything about how specific this is. Check the certifier’s website, it says, to see whether the product treats the type of PFAS you are trying to remove. A regulator would not need to say that if a certification covered the lot.
This is the part almost nobody mentions. The EPA states it plainly in its guidance on identifying filters certified to reduce PFAS. Current certification standards “do not yet indicate that a filter will remove PFAS down to the levels EPA has now set”. It says it is working with the standards bodies to close that gap.
So a filter can be genuinely certified and still not be certified down to the number a regulator considers safe. Those are two different bars, and only one of them is printed on the box.
Every reduction figure you have ever read was measured on fresh media at a controlled flow rate. Your house is not a laboratory. Your flow rate changes when someone runs a tap upstairs. Your pressure is whatever the main gives you that day. Your media has been working since the day it went in.
The EPA is direct about the consequence. Filters, it says, are only effective if they are maintained according to the manufacturer’s instructions for how long they last before replacement. Capacity is finite in every filter ever made, and a filter past its capacity stops doing the job quietly.
| What the label suggests | What was actually tested |
|---|---|
| Removes PFAS | Reduces particular named PFAS compounds, not the whole family |
| Reduces up to 99 per cent | Achieved on prepared laboratory water at a fixed flow rate |
| Certified performance | Measured on a new cartridge, not one part way through its life |
None of that makes certification worthless. It makes it a specific, bounded claim being sold as a general one.
PFAS gets into water upstream of your property, not inside it.
The routes are well documented. Firefighting foams at airfields and training grounds. Industrial sites, landfill leachate and wastewater discharge. Rainwater then carries any of it into surface water, or down through soil into groundwater. It is a catchment and source water issue.
That makes it different from the metals people often lump in with it. Lead and copper genuinely can enter water inside your house, leaching from older fittings and solder into water that left the treatment plant clean. PFAS does not work that way. Your pipes are not making it, and no amount of pipe age or corrosion creates it.
Worth knowing, because the two problems get sold together and they do not behave the same.
More closely than most people assume, and the numbers are public.
Water Corporation has run an ongoing statewide monitoring program for PFAS since 2019, in liaison with the Department of Health. The laboratories it uses detect down to one nanogram per litre. That is one part per trillion, which Water Corporation describes as the equivalent of one drop in 20 Olympic swimming pools.
On what that monitoring finds, the wording is worth quoting exactly rather than paraphrasing. Current sampling, Water Corporation says, “shows no detections above the new draft guideline values in any scheme water supplied to customers”. It describes all scheme drinking water it supplies as “fully compliant with both the current and new draft guidelines” for PFAS.
The guideline values themselves were tightened recently. In 2025 NHMRC finalised updated health based guideline values for four PFAS compounds. They are 8 nanograms per litre for PFOS, 200 for PFOA, 30 for PFHxS and 1000 for PFBS. NHMRC notes most supplies were already below the new figures. Each one has its own fact sheet in the Guidelines.
On the broader question, Water Corporation states that state and federal health authorities “have not identified public health and safety concerns related to PFAS for the general Australian population”. That is their assessment rather than ours. It is also the assessment of the bodies whose job it is to make one.
Mostly not from your tap, on the regulator’s own numbers.
Water Corporation estimates that up to 90 per cent of PFAS exposure comes from sources other than drinking water. It lists them: food packaging, cosmetics, sunscreen, paint, cleaning and stain protection products, non-stick cookware, water repellent clothing. PFAS has been used so widely that trace amounts turn up across most urban environments.
Sit that next to the marketing and the mismatch is obvious. A great deal of money is being spent on what the exposure estimates put at the small end of the problem. It is being spent on a claim that does not mean what it appears to mean.
If PFAS concerns you, the cookware and packaging in your kitchen are a larger share of your exposure than the water in your glass. That is an uncomfortable thing for a water business to write down. It is what the numbers say.
There are situations where the general picture is the wrong one to work from.
Some sites are a special case. If you are near an airfield, a defence facility or a firefighting training ground, your situation is specific. Follow the state and federal investigations into those areas rather than a national average.
If you are on bore or tank water, none of the scheme monitoring above covers you. Nobody is testing your supply unless you arrange it. That applies to far more than PFAS.
And if a filter’s PFAS certification matters to you, the useful questions are narrow ones. Which compounds is it certified against, at what flow rate, and how long does that performance hold before the media needs replacing. Any supplier who cannot answer all three is selling you the label rather than the result.
Certified filters reduce some PFAS under test conditions. The US EPA states that some filters “have been certified to remove some PFAS chemicals”. It also says current certification standards do not yet indicate a filter will reduce PFAS to the levels EPA has set. Reduction of named compounds on a new filter is the accurate description.
No. There are thousands of PFAS compounds, and certification tests against a short list. Historically that meant PFOA and PFOS above all. The EPA advises checking the certifier’s listing to confirm a product treats the type you are concerned about. That advice would be unnecessary if certification covered them all.
Water Corporation states that current sampling shows no detections above the new draft guideline values in any scheme water it supplies. It describes that water as fully compliant with both current and new draft guidelines. Its laboratories detect down to one nanogram per litre, or one part per trillion.
Water Corporation has run an ongoing statewide monitoring program since 2019, in liaison with the Department of Health. It uses independent laboratories. PFAS is one of dozens of contaminants covered by the Australian Drinking Water Guidelines.
Water Corporation estimates up to 90 per cent comes from sources other than drinking water. Its list includes food packaging, cosmetics, sunscreen and paint. It also names cleaning and stain protection products, non-stick cookware and water repellent clothing.
No. PFAS enters water through catchments, from firefighting foams, industrial sites, landfill and runoff. Lead and copper are different. Those can leach into water from older fittings inside a property, after it has left the treatment plant.
Sam Licastro comes from a plumbing trade background and previously managed at an ASX listed plumbing supplier. He tests water in Perth homes and has readings from more than 100 of them. You can read more about who writes this.
This article is general information, not medical advice. If you have a specific health concern about PFAS, speak to your GP or your state Department of Health.
The useful move with any water question is a reading rather than a guess. Tell us your suburb and we will look up what your supply reports. Or start with what chlorine turns into on the way to your tap.
