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Does reverse osmosis remove microplastics from drinking water? Yes — and it’s the most effective home filtration method available. RO membranes have pores of approximately 0.0001 microns. Microplastics, by scientific definition, start at 1 micron. That’s a 10,000× size gap. The physics are unambiguous.

Here’s what the research says, how RO compares to other filter types, and what to look for when choosing a system.

What Reverse Osmosis Actually Does

Reverse osmosis forces water through a semi-permeable membrane under pressure. The membrane’s pores are approximately 0.0001 microns — small enough to block dissolved salts, heavy metals, fluoride, and particles far smaller than any microplastic.

Microplastics range from 1 micron (about 1/70th the width of a human hair) to 5 millimeters. Even the smallest microplastic particles are thousands of times larger than an RO membrane’s pores. Physical exclusion is near-complete for particles in the microplastic size range.

What the Research Shows

A 2018 global study found microplastics in 81% of tap water samples tested across multiple continents.1 A separate 2018 study detected microplastics in 93% of bottled water brands tested.2

RO systems remove >99% of microplastics in controlled testing. The mechanism — physical pore exclusion — makes this predictable across particle sizes. A 2020 Czech study found that large municipal water treatment plants removed 70–80% of microplastics using multi-stage filtration that includes membrane steps.3 Household RO systems use tighter membranes (0.0001 µm vs. the larger pores in industrial processes), so removal rates in the home setting are consistently reported at >99%.

No other common home filter matches RO’s performance:

Filter type Examples Removes microplastics?
Activated carbon pitcher Brita, PUR No — pores too large
Ceramic filter Doulton, Berkey Partial — catches >0.5 µm only
Hollow-fiber LifeStraw, Sawyer Mostly — catches >0.1–0.2 µm
Reverse osmosis AquaTru, Waterdrop, iSpring Yes — catches >0.0001 µm

Standard pitcher filters improve taste and remove chlorine. They are not designed for particle removal and should not be used as a microplastic solution.

Why This Matters

Studies now detect microplastics in human blood, lung tissue, and cardiac tissue. Whether chronic low-level exposure causes measurable harm in adults is still being studied — the exposures are real, and drinking water is one of the highest-volume daily sources. Filtering it is the single most impactful reduction you can make.

For a full picture of where microplastics come from and how to reduce total exposure, see our guide to reducing environmental toxin exposure. For a complete comparison of filter types including PFAS and heavy metal removal, see our evidence-based water filtration guide.

What You Can Do

  1. If you rent or want a countertop option: The AquaTru Countertop RO System requires no plumbing or installation. It uses a 4-stage RO process and produces filtered water in batches. Independent testing confirms >99% microplastic removal. Downside: the tank holds about 1 gallon and takes 10–15 minutes to refill, so it works best for households that plan ahead rather than filling on demand.

  2. If you own your home: Under-sink systems (Waterdrop G3, iSpring RCC7) connect to your cold-water line and filter continuously at the tap. Higher upfront cost, significantly lower cost per gallon long-term.

  3. Replace your RO membrane on schedule. Most membranes last 2 years. A membrane past its service life loses removal efficiency. Most systems include an indicator or app reminder.

  4. For a full price-point comparison of RO and non-RO options, see our guide to the best water filters for microplastics.

This article is for informational purposes only and does not constitute medical advice.

Frequently Asked Questions

Does reverse osmosis remove microplastics from drinking water?
Yes. RO membranes have pores of 0.0001 microns — microplastics are at least 1 micron, so they are physically blocked. Studies confirm >99% removal in home RO systems.
What percentage of microplastics does an RO filter remove?
Research supports over 99% removal for home RO systems. The physical mechanism — pore size far smaller than any microplastic particle — makes near-complete removal predictable regardless of particle type.
Does a Brita filter remove microplastics?
No. Brita and similar pitcher filters use activated carbon, which is effective for taste and chlorine but does not reliably filter microplastic particles. Hollow-fiber filters catch most microplastics (particles >0.1–0.2 µm) but miss the smallest fragments. Reverse osmosis is the most complete solution.
Is RO-filtered water safe to drink long-term?
Yes. RO-filtered water is safe. Because RO also removes calcium and magnesium, some people add a remineralization stage — but mineral intake from water is a small fraction of total dietary intake and not required.
What is the difference between reverse osmosis and a regular water filter?
A standard activated carbon filter improves taste and removes some contaminants but leaves particles intact. RO adds a pressurized membrane stage that removes dissolved minerals, heavy metals, and all microplastic particles that carbon filters miss.

  1. Kosuth, M., Mason, S.A., & Wattenberg, E.V. (2018). Anthropogenic contamination of tap water, beer, and sea salt. PLOS ONE, 13(4), e0182393. https://doi.org/10.1371/journal.pone.0182393 ↩︎

  2. Mason, S.A., Welch, V.G., & Neratko, J. (2018). Synthetic polymer contamination in bottled water. Frontiers in Chemistry, 6, 407. https://doi.org/10.3389/fchem.2018.00407 ↩︎

  3. Pivokonský, M., et al. (2020). Occurrence of microplastics in raw and treated drinking water. Science of the Total Environment, 723, 137831. https://doi.org/10.1016/j.scitotenv.2020.137831 ↩︎