PFAS in drinking water has become a growing concern for Australian households. If you are looking for an additional level of treatment at home, you may be wondering whether a reverse osmosis system can reduce PFAS.
The short answer is yes — reverse osmosis is one of the treatment technologies used to reduce many PFAS compounds in water. However, performance depends on the type of PFAS, the membrane, operating conditions and the specific system being used.
What Are PFAS?
PFAS stands for per- and polyfluoroalkyl substances, a large group of human-made chemicals that have been used in products designed to resist heat, grease, stains and water.
Because these chemicals are persistent, some PFAS can remain in the environment for long periods.
Australia’s National Health and Medical Research Council updated the Australian Drinking Water Guidelines for PFAS in June 2025. The current health-based guideline values include 8 ng/L for PFOS, 200 ng/L for PFOA, 30 ng/L for PFHxS and 1,000 ng/L for PFBS. (https://www.nhmrc.gov.au/about-us/news-centre/updated-australian-drinking-water-guidelines)
These guideline values relate to drinking-water quality. They should not be interpreted as meaning that every Australian household has PFAS contamination.
How Does Reverse Osmosis Reduce PFAS?
Reverse osmosis uses pressure to move water through a specialised membrane.
The membrane separates water from many dissolved substances that are small enough to pass through ordinary sediment filtration.
This makes RO fundamentally different from a basic sediment filter. Instead of only capturing visible particles, reverse osmosis provides membrane separation for a much broader range of dissolved substances.
Australian PFAS guidance identifies high-pressure membrane systems alongside granular activated carbon and anion exchange as commonly used PFAS treatment technologies. NHMRC supporting material notes that reverse osmosis can achieve very high removal of longer-chain PFAS such as PFOA and PFOS and is also likely to remove shorter-chain compounds such as PFHxS and PFBS. (https://guidelines.nhmrc.gov.au/australian-drinking-water-guidelines/part-5/physical-chemical-characteristics/cas-numbers-1763-23-1-pfos-335-67-1-pfoa-355-46-4-pfhxs)
Does That Mean Every RO System Is PFAS Certified?
No.
This is an important distinction when comparing water filters.
Evidence showing that reverse osmosis technology can reduce PFAS does not prove that every RO system will achieve the same result.
Actual performance can vary according to:
- membrane condition and specification
- incoming PFAS concentration
- water pressure and temperature
- flow rate
- other substances present in the water
- filter and membrane age
- maintenance and replacement intervals
If a manufacturer makes a specific certified PFAS reduction claim, check which individual model was tested and under which standard.
Do not assume a certification held by one product automatically applies to every product made by the same company.
RO or Carbon Filtration for PFAS?
Activated carbon can also reduce certain PFAS, but the effectiveness depends on the carbon media, PFAS type, contact time and filter capacity.
This is one reason homeowners should avoid choosing a filter simply because its marketing material says “carbon” or “RO”.
The appropriate system depends on what you are trying to achieve.
For households primarily concerned about drinking and cooking water, an under-sink RO system provides a targeted treatment point at the kitchen.
For homeowners wanting filtration throughout the property, a whole-house system serves a different purpose. Depending on the water-quality objective, some homes use whole-house filtration together with a separate RO drinking-water system.
Should You Test Your Water for PFAS?
If you have a specific reason to suspect PFAS contamination, laboratory testing provides much more useful information than a general TDS reading.
A TDS meter measures the overall concentration of dissolved ions in water. It does not identify PFAS or tell you which individual PFAS compounds are present.
Knowing the actual water-quality issue makes it easier to select an appropriate treatment approach.
Choosing an RO System for Your Home
When comparing reverse osmosis systems, look beyond a single contaminant claim.
Consider membrane performance, filtration stages, replacement costs, purified-water flow, installation requirements, ongoing maintenance and whether performance claims are supported by appropriate testing or certification.
HG PureWater offers under-sink reverse osmosis systems for Australian homes, including the high-flow tankless HGH-24 and compact HGH-26. The HGH-24 uses an 800 GPD RO membrane and is designed to provide up to approximately 2.1 litres of purified water per minute under suitable operating conditions.
If PFAS is your main concern, start by understanding your water source and the level of treatment you actually need rather than choosing a system based on one marketing claim.
Need Help Reviewing the Options?
Contact HG PureWater with your water source, postcode, available test results and intended use. We can help you compare suitable next steps without assuming that one system is appropriate for every property.
