The EPA finalized national PFAS drinking water standards on 26 April 2024, setting maximum contaminant levels of 4.0 parts per trillion for PFOA and PFOS. Initial monitoring is required by 26 April 2027, so for most water systems the honest answer today is that measurement is still under way.
What PFAS are
Per- and polyfluoroalkyl substances are a family of thousands of synthetic compounds built around carbon-fluorine bonds — among the strongest in organic chemistry, which is exactly why they are useful and exactly why they persist. They have been used since the 1940s in non-stick coatings, stain-resistant fabrics, food packaging and firefighting foam. The nickname "forever chemicals" is about that persistence, not about any particular toxicity claim.
They enter drinking water from industrial discharge, from firefighting foam use at airports and military bases, from landfill leachate, and from land application of sewage sludge.
The regulation, precisely
Loose reporting on PFAS is everywhere, so here are the dates and the numbers as published:
- 26 April 2024 — the PFAS National Primary Drinking Water Regulation was published in the Federal Register. It set enforceable maximum contaminant levels of 4.0 parts per trillion each for PFOA and PFOS, with limits for several other PFAS compounds.
- 26 April 2027 — the deadline for initial monitoring. Water systems must have measured and must inform the public of the results.
- 18 May 2026 — the EPA proposed extending the MCL compliance deadline from April 2029 to April 2031 via an exemption framework, while keeping the 4.0 ppt levels themselves intact.
Four parts per trillion is a genuinely small number — roughly four drops in an Olympic swimming pool — and it was set that low because the health analysis supported it, not because it is convenient to measure.
What that timeline means for you today
It means that for many water systems, nobody has finished measuring yet. If your utility has published results, read them. If it has not, that is not negligence — it is the schedule the rule laid out. Some states have moved faster than the federal timetable and have their own limits and published data.
Two situations raise the probability enough to be worth acting on before your utility reports: living near a military base, airport or fire training facility where fluorinated foam was used, and living near known industrial PFAS discharge. Those are the sources most consistently linked to elevated drinking water levels.
What removes PFAS
| Technology | Effective for PFAS? | Notes |
|---|---|---|
| Reverse osmosis | Yes — the strongest option | Systems certified under NSF/ANSI 58 for PFOA/PFOS carry the claim explicitly |
| Activated carbon, certified | Yes, with the right certification | Look for NSF/ANSI 53 covering PFOA/PFOS, or the NSF P473 protocol |
| Ion exchange resin | Yes | Used at municipal scale; certified consumer products exist |
| Standard carbon, uncertified | Unreliable | Some reduction, no verified claim, no capacity data |
| Boiling | No — makes it worse | PFAS do not evaporate; boiling concentrates them |
| Water softener | No | Ion exchange for hardness is a different resin and a different job |
NSF P473 is a protocol written specifically for PFOA and PFOS, tested at concentrations relevant to the EPA limit. It is the most targeted certification available and it is worth looking for by name.
The certification gap that catches people
A filter certified for lead is not automatically certified for PFAS. The most common real-world example: the Brita Elite is certified to NSF/ANSI 53 for lead, and per Brita's January 2026 performance data sheet it is not certified for PFOA or PFOS. Meanwhile the ZeroWater 5-stage filter is IAPMO-certified against NSF/ANSI 53 for PFOA and PFOS.
Two pitchers, same shelf, opposite answers to a PFAS question. Check the specific contaminant, not the brand — that is the whole lesson of this hub, and PFAS is where it costs the most.
Which products, specifically: the PFAS filter roundup.
Questions people actually ask
How do I find out if there is PFAS in my water?
Check whether your utility has published PFAS monitoring results — many have, and more will as the April 2027 initial monitoring deadline approaches. If nothing is published and you live near a known source such as a military base or airport, a PFAS-specific laboratory test is the only way to get a number.
Does boiling remove PFAS?
No, and it makes things worse. PFAS do not evaporate with the water, so boiling reduces the volume and concentrates them. Boiling addresses microbiological risk only.
Does a Brita filter remove PFAS?
No. Per Brita's January 2026 performance data sheet, the Brita Elite is not certified for PFOA or PFOS, and neither is the Standard filter. If PFAS is your concern, you need a filter that carries that specific certification — ZeroWater's 5-stage filter does.
Is bottled water free of PFAS?
Not necessarily. Bottled water is regulated as a food product and is not required to be tested against the same PFAS limits as public drinking water. Some brands publish their own results; many do not. It is not a reliable way around the problem.
Sources
- EPA — PFAS National Primary Drinking Water Regulation (Federal Register, 26 April 2024)
- EPA — announcement that maximum contaminant levels for PFOA and PFOS are retained
- EPA — proposed PFOA and PFOS compliance extension rule
- NSF — Certified Products and Systems
- Tap Score (SimpleLab) — what Brita pitchers filter out, citing Brita's January 2026 performance data sheet