When you pour a glass of water, it looks pure. Yet the EPA is now treating microplastics as a serious drinking-water issue precisely because some of the most important contaminants are invisible. On April 2, 2026, the agency released its draft Sixth Contaminant Candidate List, or CCL 6, and for the first time in the program’s history it included microplastics as a priority contaminant group. In EPA’s system, that is not a final regulation. It is an official signal that a substance may occur in public water systems, may matter for public health, and deserves focused research, monitoring, and possible future rulemaking under the Safe Drinking Water Act. (epa.gov)
Why now? EPA gives several reasons. The agency says it recognizes growing concern about microplastics in drinking-water sources, and it also received a public nomination asking that microplastics be added to CCL 6. In addition, EPA’s Science Advisory Board had previously encouraged the agency to assess microplastics for future candidate lists. The deeper reason is scientific uncertainty: EPA says there are still major data gaps, but those gaps are exactly why the agency wants to move. Officials say they still need a health-based definition that identifies which kinds of particles are most strongly linked to harm, and they need validated analytical methods that can reliably detect and measure microplastics in drinking water. In other words, EPA is acting because the risk cannot yet be fully measured, not because the problem has been solved. (epa.gov)
That makes microplastics a particularly modern pollutant. EPA researchers describe them as plastic particles ranging from 5 millimeters down to 1 nanometer, including both intentionally manufactured particles and fragments shed from larger plastics such as packaging, tires, and synthetic textiles. EPA also notes that microplastics have been found in food, beverages, and human and animal tissue, which helps explain why public anxiety has grown. For now, CCL 6 does not impose new requirements on water systems, but EPA is accepting public comments until June 5, 2026, and expects the final list to be signed by November 17, 2026. After that, the agency must decide whether to regulate at least five contaminants from the final list in a separate process. (epa.gov)










