Microplastics — plastic fragments smaller than 5 millimeters, and the even tinier nanoplastics under a micron — have gone from a niche worry to one of the most-searched water topics. The reason is simple: researchers keep finding them everywhere, including in us.
What the research shows
A 2025 study in Nature Medicine found microplastics and nanoplastics in human brain, liver, and kidney tissue — with higher concentrations in samples from 2024 than from 2016, suggesting accumulation is rising (the study's lab methods have since been debated, though the finding fits a wider pattern of detections). Other studies have detected them in blood, the placenta, and breast milk. The contamination appears close to universal.
The honest part: we don't fully know the health effects yet
Here's where we'll be straight with you: scientists have not established what this exposure does to human health. The presence of a particle isn't proof of harm, and major research gaps remain — the WHO has called for far more study. This is a real, fast-moving concern, not a settled danger. We'd rather tell you that than overstate it.
Bottled water isn't the safe alternative — it's usually the worse one.
Bottled vs. tap
If microplastics worry you, the instinct to reach for bottled water backfires. A 2024 Columbia University study found popular bottled-water brands contained on the order of 240,000 plastic particles per liter once nanoplastics were counted — vastly more than typical tap water, which often measures in the single digits to low hundreds per liter. The bottle itself is a major source.
What helps
Conventional treatment removes an estimated 70–90% of microplastics, but the smallest particles are the hardest to catch. There's no federal standard yet — California became the first government to require microplastics testing of drinking water, now moving to treated water in 2026–2028.
Low-regret steps
- Choose filtered tap over bottled. It usually means fewer particles, not more.
- Cut the plastic your water touches — store water in glass or stainless steel, and don't heat water in plastic.
- A quality filter helps. Reverse osmosis captures far smaller particles than most pitcher filters.