ZIP 01863: your water comes from North Chelmsford Water Dist
North Chelmsford Water Dist is the only community water system that reports serving ZIP 01863 (Middlesex County, Massachusetts) under EPA's UCMR 5. PFAS-4 at the latest sample (2024): below the 3 to 4 ng/L reporting limit. Systems report their own ZIP lists to EPA; if your water bill names another utility, that utility's page carries its own results.
Where this ZIP is
This site is a data project, not an official source. If in doubt, check with your water supplier or local authority.