Ion exchange filtration, developed in StockholmFilter water.
Filter water.
Openly measured.
Ion exchange filter cartridges for the home, developed in Stockholm. The filter medium is an anion exchange fibre in chloride form.
Ion exchange fibre
An anion exchange medium supplied in chloride form.
Free shipping
On orders over 500 SEK within Sweden.
Cancel anytime
Subscriptions pause or cancel with one click.
Developed in Stockholm
The filter medium is an anion exchange fibre.
How it works
How ion exchange filtration works
Most PFAS are acids that carry a negative charge in water. An anion exchanger holds chloride ions on its surface and can swap them for other negatively charged molecules, including PFAS.
The medium
An anion exchange fibre supplied in chloride form, with a polyacrylonitrile matrix and a fibre diameter of about 30 micrometres.
The exchange
Chloride ions held on the fibre surface are swapped for other negatively charged molecules as water passes through.
Worth knowing
Competing ions
Tap water also contains chloride, sulfate and bicarbonate, which compete for the same sites. Real world capacity depends on local water chemistry. That is what our testing is designed to measure.
Refill
One filter on a schedule. At a discount.
Pick 6 or 12 months between shipments. Skip, pause, or cancel whenever, no lock-in.
See Refill plansFrequently asked
What is PFAS?
PFAS are per- and polyfluoroalkyl substances, a large group of synthetic chemicals used since the 1940s in firefighting foam, non-stick coatings, and waterproofing. They are called forever chemicals because the carbon to fluorine bond does not break down naturally. The EU Drinking Water Directive sets a limit for the sum of 20 PFAS substances, and Sweden adds a stricter limit of 4 ng/l for four of them (LIVSFS 2022:12). Those limits apply to drinking water producers. You can read your own municipality's most recent analysis on its website.
How does the filter work?
Our filter medium is an anion exchange fibre supplied in chloride form, with a polyacrylonitrile matrix and a fibre diameter of about 30 micrometres. Most PFAS are acids that carry a negative charge in water. An anion exchanger holds chloride ions on its surface and can swap them for other negatively charged molecules, including PFAS. Because ordinary tap water also contains chloride, sulfate and bicarbonate, which compete for the same sites, real world capacity depends on local water chemistry. That is what our testing is designed to measure.
When do I replace the filter?
Every 6 months for typical household use. A Refill subscription ships a fresh cartridge automatically, on a 6- or 12-month cadence.
Does it fit my tap?
The cartridge is designed for Filterion countertop and under-sink housings. Universal-adapter support for common Swedish and European tap threads is in the box.
Is the water safe to drink immediately?
Run the tap for 30 seconds after installing a new cartridge to flush it through. After that, drink straight from the tap.
Where does Filterion ship?
Sweden, Norway, Denmark, Finland, Germany, Netherlands, France, Belgium, Italy, Spain, Austria, Ireland, Poland, Czech Republic. More EU countries rolling out.
What's the return policy?
Unopened filters can be returned for a full refund within 30 days. Used filters are non-refundable. Send a used cartridge back with your next order and we credit a discount on the next one.
What's the warranty?
Cartridges are guaranteed to perform for their rated life (6 months typical, subject to water quality). Housings carry a 2-year warranty against defects.