Does tap water have microplastics?

Yes. Tap water contains microplastics in most places tested worldwide. They enter water systems through surface runoff, aging plastic infrastructure, and atmospheric deposition. That said, research estimates tap water delivers far fewer particles than bottled water. Roughly 4,000 particles per year from tap versus around 90,000 from bottled water, though exact figures vary by study.

Does bottled water have more microplastics than tap water?

Research suggests yes, significantly more. Studies estimate bottled water drinkers ingest roughly 90,000 additional microplastic particles per year compared to about 4,000 for tap water drinkers. The plastic bottle and cap are the primary sources. Switching to filtered tap water appears to reduce exposure rather than increase it.

Do water filters remove microplastics?

Reverse osmosis systems remove the vast majority of microplastics. RO membranes have pore sizes around 0.0001 microns, far smaller than even nanoplastics. High-quality solid carbon block filters with tight pore sizes can also capture many microplastics. NSF hasn't issued a specific microplastic removal standard yet, but NSF/ANSI 58 certification (for RO systems) is currently the best benchmark to look for.

Does boiling water remove microplastics?

A 2024 study found boiling removed up to 90% of microplastics in hard water samples. The calcium carbonate scale that forms during boiling traps particles, which you then discard with the scale. The effect was smaller in soft water. This is a promising finding from one study, not a confirmed treatment method, and it doesn't work the same way for all water types.

Microplastics in Drinking Water: What the Research Actually Shows

Q: Are microplastics in drinking water dangerous?

The research is still early. A 2024 study in the New England Journal of Medicine found an association between microplastics in arterial plaque and higher rates of cardiovascular events, but the researchers noted the findings needed further investigation to establish causation. Other lab research links microplastics to inflammation and oxidative stress. The EPA hasn't set a legal limit yet and classifies this as an active research area.

Health disclaimer: The research on microplastics and human health is ongoing. This page summarizes current findings, not medical advice. If you have health concerns related to water quality, talk to your healthcare provider.

Here’s something the bottled water industry would rather you didn’t know. Bottled water contains far more microplastics than tap water. Research estimates bottled water drinkers ingest roughly 90,000 additional microplastic particles per year. Tap water drinkers? About 4,000. The exact numbers vary by study, but the direction of the finding is consistent.

That reframes everything.

What Microplastics Are

Microplastics are plastic particles smaller than 5 millimeters. Nanoplastics are even smaller, under 1 micrometer, invisible to the naked eye. Both have been detected in drinking water sources around the world.

They come from multiple places. Plastic packaging breaks down over time, shedding particles into water and soil. Synthetic textiles release fibers when washed. Tire wear leaves plastic residue on roads that runoff carries into waterways. Plastic pipes in plumbing infrastructure shed particles directly into the water supply. Even the air carries microplastics, which settle into open reservoirs.

They’re everywhere. That’s not alarmism. It’s what the data consistently shows.

How They Get Into Your Tap Water

Surface water picks up microplastics from agricultural runoff, urban stormwater, and plastic waste in rivers and lakes. Treatment plants remove a meaningful portion of particles, but not all. A 2025 study in Nature npj Clean Water looked at microplastic removal across treatment facilities and found that even well-functioning plants pass some fraction of particles through to finished water.

Plastic pipes in distribution systems add another source. As pipes age, they shed particles into the water moving through them. This is partly why treatment plant performance doesn’t tell the whole story. Water can pick up more particles on its way from the plant to your tap.

Atmospheric deposition is a smaller but real pathway. Microplastics fall from the air into open water storage.

What the Health Research Actually Shows

This is where the conversation gets complicated, so let’s be direct about what’s known and what isn’t.

A 2024 study published in the New England Journal of Medicine found an association between microplastics detected in carotid artery plaque and higher rates of cardiovascular events, including heart attack, stroke, and death, during a follow-up period. The researchers noted the findings needed further investigation to establish causation. That’s an important distinction. The study showed a statistical association. It did not prove that microplastics caused those outcomes.

Other research, mostly in lab settings, has linked microplastic exposure to inflammation and oxidative stress. These findings come from cell studies and animal models. They’re worth paying attention to. But they don’t establish a causal chain in humans.

The honest summary: there are real reasons for concern, real research underway, and a real gap between what we currently know and what would constitute proof of harm. The science is moving fast. What’s true today may be better characterized in two years.

The EPA’s Position

The EPA has not set a Maximum Contaminant Level for microplastics. No enforceable limit exists in US drinking water law right now. The agency is in active research mode, gathering data on occurrence, exposure, and potential health effects.

That’s not the same as saying microplastics are safe. It means the regulatory process hasn’t reached the point of setting a standard. EPA MCLs require a defined analytical method, exposure data, and a dosed risk assessment. For microplastics, that work is still ongoing.

The Boiling Water Finding

A 2024 study found that boiling tap water removed up to 90% of microplastics in hard water samples. The mechanism is simple: when hard water boils, calcium carbonate scale forms and traps microplastic particles. You pour off the water and discard the scale, taking most of the particles with it.

In soft water, the effect was smaller. Soft water doesn’t form the same mineral scale, so fewer particles get captured.

This is a promising single-study finding. It’s not a confirmed treatment protocol. And boiling doesn’t help with other contaminants the way filters do. But if you have hard water and no filtration, it’s a reasonable interim step.

What Filters Actually Work

Reverse osmosis is the most reliable option. RO membranes filter at 0.0001 microns, smaller than even nanoplastics. An NSF/ANSI 58 certified RO system removes the vast majority of microplastics at the point of use, along with a long list of other contaminants including PFAS and lead.

High-quality solid carbon block filters with tight enough pore ratings can capture many microplastics too. The catch is that pore size varies widely across carbon block products. A loose 5-micron block won’t catch the smallest particles. Look for sub-micron ratings.

NSF International hasn’t issued a specific certification standard for microplastic removal yet. Until they do, NSF/ANSI 58 for RO systems is the best available benchmark.

Standard pitcher filters with activated carbon granules won’t capture most microplastics. The carbon adsorbs chemicals, not particles. Granular carbon beds have wide channels between particles. Check the filtration rating before buying.

The Direct Recommendation

If microplastics concern you, an NSF/ANSI 58 certified under-sink RO system is the most reliable point-of-use option right now. It removes microplastics along with dozens of other contaminants with documented health risks.

And if you’re drinking bottled water to avoid tap water microplastics, the research suggests you’re doing the opposite of what you intend. A quality filter on your tap water puts you in a better position than bottled.

For filter options, see our best under-sink RO systems review. If you don’t know what’s in your water yet, start with water testing before buying any treatment system.

Sources:

Schwabl P, et al. Detection of Various Microplastics in Human Stool. Annals of Internal Medicine, 2019. PMC microplastics review
Microplastic removal at drinking water treatment facilities. Nature npj Clean Water, 2025. Full study
Marfella R, et al. Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. New England Journal of Medicine, 2024.

Health disclaimer: WaterAnswer.com provides general educational information only. This page does not constitute medical advice. Consult your healthcare provider with specific health concerns.