Bottom line: 81% of tap water samples tested across 14 countries contained microplastic fibers. The United States had the highest contamination; Europe the lowest — but no region was clean. Standard municipal treatment isn’t designed to catch particles this small.

What They Found

  • Researchers tested 159 tap water samples from 14 countries, including the US, UK, France, Germany, Uganda, India, Indonesia, Lebanon, and Ecuador.
  • 81% of samples contained microplastic fibers — the vast majority being synthetic textile fibers rather than fragments.
  • US samples averaged 4.8 particles per liter (the highest rate of any country tested).
  • European samples averaged 1.9 particles per liter — still positive, just lower.
  • Most particles were under 5 mm and came from synthetic clothing, atmospheric deposition, and aging water infrastructure.

What You Can Do

  1. Filter your water with the right technology. Standard activated-carbon pitchers catch some particles but not all. See our breakdown of the best water filter for microplastics — reverse osmosis and sub-micron hollow-fiber filters are the two technologies with strong removal evidence.
  2. Don’t switch to bottled water. Other research (Mason et al. 2018) found bottled water contains roughly twice as many microplastic particles as tap water on average. The plastic bottle itself is a source.
  3. Reduce your other exposures. Water is only one route. Our deep dive on microplastics in human blood covers the full picture — food storage, tea bags, synthetic textiles, indoor air.

Frequently Asked Questions

How much microplastic is in tap water?
A 2018 global study found an average of 4.8 particles per liter in US tap water and 1.9 particles per liter in European tap water. 81% of all samples tested contained some microplastic contamination.
Does boiling water remove microplastics?
No. Boiling kills pathogens but does nothing to plastic particles. Some research suggests boiling may reduce nanoplastic counts in hard water by co-precipitating them with limescale, but filtration is more reliable.
Is bottled water safer than tap water for microplastics?
No — it’s generally worse. A 2018 study of bottled water from 9 countries found roughly twice the particle count of tap water. The plastic bottle itself sheds particles into the water.

For a step-by-step guide to reducing microplastic exposure across all sources, see our complete environmental toxins overview.

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

Source: Kosuth, M., Mason, S. A., & Wattenberg, E. V. “Anthropogenic contamination of tap water, beer, and sea salt.” PLOS ONE, Volume 13, Issue 4, 2018. DOI