PFAS have been in the news for years, and pharmaceutical residue in water is a question we hear more each season. Here is what they are, whether you should worry, and which treatment actually removes them.
What PFAS are
Per- and polyfluoroalkyl substances are a family of thousands of manufactured chemicals used since the 1950s in non-stick coatings, stain and water repellents, firefighting foam and food packaging. They are extremely stable, which is the point of them and the problem with them: they do not break down, and they have spread through water, soil and people worldwide. In 2024 Health Canada set a drinking water objective for the combined total of a group of PFAS, replacing its older limits for individual compounds. The Health Canada PFAS objective is 30 ng/L for the sum of 25 PFAS, with levels kept as low as reasonably achievable.
What pharmaceutical residue is
Medications pass through people and animals and into wastewater and septic systems. Treatment plants and soil remove most but not all, and trace amounts reach rivers, lakes and groundwater. Levels in drinking water are very low. The concern is long-term, low-dose exposure, and the science is still developing.
Should you worry?
York Region publishes its municipal drinking water test results every year, on its drinking water quality and monitoring page. Private wells near former industrial sites, airports, firefighting training areas or downstream of septic systems are where a specific concern makes sense. For everyone else it is a personal decision, and the only way to make it on facts is a lab test. PFAS testing through an Ontario lab is available on request.
What does not reliably work
Pitcher filters, fridge filters and basic carbon cartridges. Some are certified to reduce specific PFAS compounds, usually only a few of them, and performance drops as the cartridge ages. Most do little for pharmaceutical residue. Softeners, sediment filters and UV do nothing at all for either.
What does
Reverse osmosis rejects the large majority of PFAS compounds and most pharmaceutical residue at the membrane. Specialty activated carbon and ion exchange media designed for PFAS add a second barrier. We combine them in an under-sink system at the kitchen tap, feeding the fridge and ice maker too. The Honest Water reverse osmosis system, built in Barrie, Ontario, is the starting point. Our PFAS and pharmaceuticals page covers the design.
What to look for in a drinking water system
Not every under-sink system is built for PFAS. A few things separate one that will do the job from one that only improves taste:
- A true reverse osmosis membrane, not just carbon cartridges in a row.
- Pre-filters that protect the membrane from sediment and chlorine, changed on schedule.
- Independent certification of the claims the manufacturer makes, rather than marketing wording.
- A lead-free faucet, so the last few centimetres do not undo the treatment.
- A service plan, because a membrane that is never checked eventually stops rejecting what it should.
Water pressure and hardness matter too. Low pressure reduces how well a membrane rejects contaminants and how fast the tank fills, and very hard water shortens membrane life. We check both before we recommend a system.
Why not the whole house?
Whole-home PFAS treatment exists, using large specialty media tanks, but it is expensive and the spent media needs careful disposal. You drink and cook with a few litres a day. Treating those few litres properly is the practical answer for almost every household.
Where to start
On town water, the fix is simple. Put reverse osmosis at the kitchen tap and drink from it. We check the basics that affect how an RO system performs, such as hardness, chlorine and dissolved solids, and we can arrange a PFAS lab test if you want the numbers for your own tap. If you are on a well in a rural part of Georgina or East Gwillimbury, a lab test is the only record of what your own water contains. Start with in-depth well water testing.
Common questions
Does a water softener remove PFAS?
No. A household softener exchanges hardness minerals and is not designed or certified to reduce PFAS. Neither are sediment filters or UV. Reverse osmosis is the treatment that reliably does.
Does boiling water remove PFAS?
No. PFAS do not break down with heat, and as water boils off, what remains is slightly more concentrated. Boiling is for germs, not chemicals.
Do pitcher or fridge filters remove PFAS?
Some are certified to reduce specific PFAS compounds when the cartridge is new. Look for a certification that names PFAS reduction, change the cartridge on schedule, and know that performance falls as it fills. Reverse osmosis gives a much wider and more consistent margin.
Does reverse osmosis remove pharmaceuticals?
Reverse osmosis rejects most pharmaceutical residue at the membrane, and carbon after it catches much of what is left. No home system removes everything, which is why we would rather show you a lab result than make a blanket promise.
How do I test my water for PFAS?
PFAS need a specialised lab method that a home test strip cannot do. PFAS testing through an Ontario lab is available on request, and the report comes back to you, not just to us.
Is my private well more at risk than city water?
Only if there is a likely source nearby, such as a former industrial site, an airport, a firefighting training area or heavy septic loading upstream. Municipal systems are monitored; private wells are not, so on a well a lab test is the only way to know.