Unregulated contaminants are those for which EPA has not established drinking water standards. The purpose of unregulated contaminant monitoring is to assist EPA in determining the occurrence of unregulated contaminants in drinking water and whether future regulation is warranted. UCMR testing provides scientifically valid data on the occurrence of these contaminants in drinking water. Health research is necessary to know whether these contaminants pose a health risk. Water systems across the country are collecting samples for the Fifth Unregulated Contaminant Rule (UCMR5) during four consecutive quarters between January 2025 and December 2025. Bethesda Water Supply conducted most of its required testing in February, May, August, November 2025. Complete results for all four quarters of testing at all plants have been posted here (read report). For the UCMR5, EPA selected 29 per- and polyfluoroalkyl substances (PFAS) and one metal/pharmaceutical — lithium. PFAS are a group of synthetic chemicals used in a wide range of consumer products and industrial applications. These include: • non-stick cookware • water-repellent clothing • stain-resistant fabrics and carpets • cosmetics • firefighting foams • electroplating • products that resist grease, water, and oil PFAS are found in the blood of people and animals and in water, air, fish, and soil at locations across the world. Bethesda Water Supply tested 29 PFAS contaminates detecting on 1 PFAS and Lithium.
You may view the report below or click here (Report)
