When people pour a glass of water, they usually think of something pure and simple. But scientists keep finding tiny plastic pieces in drinking water. These pieces are called microplastics, and the even smaller ones are called nanoplastics. According to the World Health Organization, they can enter drinking-water sources through surface runoff, wastewater, industrial effluent, degraded plastic waste, atmospheric deposition, and even plastic bottles and caps themselves. (cdn.who.int)
Recent research shows why this topic is getting so much attention. A 2024 study in the Proceedings of the National Academy of Sciences, summarized by the U.S. National Institutes of Health, found that one liter of bottled water contained about 240,000 plastic particles on average. About 90% were nanoplastics, which are so small that they may enter cells and tissues more easily than larger particles. (nih.gov)
At the same time, scientists are still trying to answer the biggest question: how dangerous are these particles for human health? The WHO’s drinking-water review said the evidence was limited, and the U.S. FDA says current scientific evidence does not show that the levels found in foods, including bottled water, pose a risk to human health. The U.S. EPA also says it is still developing better methods to measure microplastics and study their health effects, especially for nanoplastics. (cdn.who.int)
What is changing fastest now is regulation. In the United States, the EPA announced on April 2, 2026 that microplastics were included for the first time in the draft Sixth Contaminant Candidate List for drinking water. This does not create a national legal limit yet, but it is an important first step toward future federal monitoring and possible regulation. California has already gone further: the State Water Board adopted a definition, standard testing methods, and four years of testing and reporting with public disclosure. (epa.gov)
Europe is moving too. In 2024, the European Commission set a harmonized method to measure microplastics in water intended for human consumption. EU materials published in 2025 say the revised Drinking Water Directive requires a full risk assessment of microplastics in drinking water by 2029, and the EU has also adopted new rules to reduce plastic pellet losses, a major source of microplastic pollution. In short, the health science is still developing, but governments are no longer waiting to start measuring the problem more seriously. (environment.ec.europa.eu)










