Guide · July 28, 2026

What water filter removes microplastics?

Two filter types are physically consistent removers: reverse osmosis and ultrafiltration. Everything else — Brita, PUR, ZeroWater, even Berkey's marketed claims — is either uncertified for microplastics specifically or verified mostly by the manufacturer, not a third party. We tested each individually. Here's the side-by-side verdict.

The comparison

Filter	Mechanism	Microplastic removal	Typical cost
Reverse Osmosis	0.0001 µm membrane	Excellent — physics, not a claim	$150–$400 under-sink
Ultrafiltration (UF)	0.01 µm membrane	Very good — physics, not a claim	$100–$300
Carbon block (tight)	Depends on pore rating	Moderate — varies by model	$30–$100
Berkey (Black Berkey elements)	Ceramic + carbon block	Claims >99.9%; mostly in-house testing	$300+ system
ZeroWater 5-stage pitcher	Ion exchange + carbon	Inconsistent — not certified	$25–$45
Brita / PUR pitcher or faucet	Activated carbon	Inconsistent — not certified	$20–$40

Why pore size is the whole question

Microplastic particles run roughly 1–100 microns. Reverse osmosis membranes have pores around 0.0001 µm — about 10,000x smaller than the smallest particle in that range — so removal is a function of physics, not a marketing claim. Ultrafiltration sits at roughly 0.01 µm, still tight enough to be a consistent barrier.

Standard pitcher and faucet filters (Brita, PUR, ZeroWater) run on activated carbon and ion exchange, which are built and certified for chlorine taste, a handful of metals, and some pharmaceuticals — not particulate matter at microplastic sizes. A 2022 comparative study (Pivokonsky et al.) found granular activated carbon meaningfully less effective at microplastic removal than tighter membrane filters. That doesn't mean a carbon pitcher does nothing — it means there's no certification and no consistency to lean on.

Berkey is the outlier: gravity-fed ceramic + carbon elements the company claims remove >99.9% of a long list of contaminants, including plastics, from its own internal lab testing. Plausible given the tighter ceramic media, but independent third-party verification specific to microplastics is thin. Worth testing yourself if you own one.

Test your own filter

Certifications tell you what a filter was built for. They don't tell you what your specific unit, at its current age, is doing right now. The Water Test in-home kit ($75, tests sold separately) runs a before/after comparison: one 100 mL sample from the unfiltered tap, one from your filter's output. The filtered-water testing guide walks through the exact protocol for a pitcher, a fridge dispenser, or an RO system.

Microplastic particles glowing pink under blue light on a filter disc — at-home Water Test kit result

A real in-home test result. Run it on your filter's output to see what it's actually catching.

Per-filter teardowns

Common questions

What water filter actually removes microplastics?

Reverse osmosis (pore size around 0.0001 µm) and ultrafiltration (around 0.01 µm) are the consistent removers — the pores are physically smaller than the particles. A tight carbon block helps depending on its pore rating. Standard activated-carbon pitchers (Brita, PUR, ZeroWater) are inconsistent and not certified for microplastic removal.

Does Brita or PUR remove microplastics?

Neither is NSF-certified for it. Both use activated carbon, which can trap some larger particles on the first passes through the bed, but a 2022 comparative study (Pivokonsky et al.) found granular activated carbon less effective than tighter membranes. Full breakdowns: does Brita remove microplastics and does PUR remove microplastics.

Is ZeroWater any better than Brita for microplastics?

ZeroWater's 5-stage filter is tighter than a basic carbon pitcher, but the company doesn't publish a pore size for the stage that would matter and carries no NSF certification for microplastics either. Full breakdown: does ZeroWater remove microplastics.

Does a Berkey actually remove microplastics?

Berkey claims >99.9% removal on a long list of contaminants from internal lab testing, but independent third-party verification specific to microplastics is thin. Treat it as a strong claim, not a certified one, until you test your own. Full breakdown: does Berkey remove microplastics.

Is reverse osmosis worth it just for microplastics?

If microplastics are the only reason, it's the most expensive way to solve it — but it's also the one filter type that removes them by physics rather than by claim. The membrane's pores are about 10,000x smaller than the smallest microplastic. Full breakdown: does reverse osmosis remove microplastics.

How do I know if my specific filter is working?

Test it. Fill one 100 mL sample from the unfiltered tap and a second from your filter's output, run both through an in-home microplastics kit, and compare the two filter discs side by side. Manufacturer certifications tell you what a filter is built for — they don't tell you what your unit, at your filter age, is actually doing today.

Guide