Ansonia Water Hardness & Quality Report (2026)

Ansonia, Connecticut, in the Naugatuck Valley Planning Region — a Naugatuck Valley borough adjacent to Derby and Shelton, in the lower Naugatuck River valley of New Haven County, a historic industrial city in the Brass Valley manufacturing corridor — receives its municipal water from the Valley Water Authority or the Ansonia Water Division, drawing from the Naugatuck River watershed reservoirs in the western Connecticut Upland.

The extremely soft 25.5 mg/L hardness and very low TDS of 41.8 mg/L reflect the Naugatuck watershed's Western Connecticut crystalline rock character — among the softest water in any Connecticut city. The Naugatuck River headwaters drain the Western Connecticut Upland (Precambrian Derby Gneiss and Rowe Schist — insoluble silicate metamorphic rock), with minimal carbonate contact except in the narrow Hartford Basin margin. The result is the very soft, near-pure rainwater-derived supply characteristic of the Connecticut upland river sources.

At 25.5 mg/L, Ansonia's water is extremely soft — no scale ever forms, soap lathers maximally, and appliances achieve maximum lifespan. No descaling is needed. The PFAS level of 5.5 ppt warrants a certified drinking water filter — the Naugatuck Valley Brass Valley industrial legacy (Ansonia Copper and Brass, Chase Brass — PFAS from industrial process chemicals), the Sikorsky Aircraft corridor (Stratford, CT), and the lower Naugatuck PFAS industrial corridor contribute to Ansonia's elevated readings despite its pure source water.