While the tap water in Nassau County, NY, is legally classified as "safe to drink" by the EPA and local health departments, it is a subject of significant local debate in 2026 due to persistent contaminants. The water is primarily sourced from the Magothy Aquifer, and recent reports have highlighted elevated levels of 1,4-dioxane, PFAS (forever chemicals), and nitrates from industrial and agricultural runoff. While the county has invested over $120 million in advanced filtration systems to remove these "emerging contaminants," many residents still prefer using high-quality point-of-use filters (like reverse osmosis or activated carbon blocks) to further reduce trace minerals and chemical odors. If you are in an older home, there is also the added risk of lead leaching from aging pipes. For visitors in 2026, the water is perfectly fine for showering and brushing teeth, but if you have a sensitive stomach or are concerned about long-term chemical exposure, using a filtered pitcher or opting for bottled water is a common and cautious practice among Nassau residents.