Do drinking water treatment plants remove most microplastics?
Often, yes. In one 2025 study, municipal treatment plants removed more than 97.5% of measured microplastics.
What is actually in it
Microplastics show up in some source water before treatment. That does not mean the same amount reaches your tap. The treatment step matters.
The old headline compared sand and membrane filters. The cited study does not support a simple home-filter ranking. It looked at 10 municipal drinking water treatment facilities and their distribution systems.
What the research says
A 2025 NPJ Clean Water study measured microplastics larger than 2 micrometers across 10 drinking water treatment facilities.
Untreated source water had 1,193 to 7,185 particles per liter. The facilities removed more than 97.5% of measured microplastics, mainly through chemically assisted granular media filtration or ultrafiltration.
This is good news, but it is not a blank check. The study looked at particles larger than 2 micrometers, and it focused on municipal systems, not every pitcher or under-sink filter.
What to do instead
Use tap water when your local water quality report looks solid. Store water in glass or stainless steel, especially if it sits in a hot car or near heat.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| Microplastic removal across ten drinking water treatment facilities and distribution systems. | NPJ Clean Water | 2025 |