Seymour Water Hardness & Quality Report (2026)

Seymour, Connecticut, in the Naugatuck Valley Planning Region — a Naugatuck Valley town adjacent to Ansonia and Derby on the Naugatuck River in south-central Connecticut — receives its municipal water from the Seymour Water Division, drawing from local reservoir sources (Naugatuck Valley) in the Connecticut Highland watershed.

The extremely soft 22.5 mg/L hardness and very low TDS of 36 mg/L make Seymour one of the softest water supplies in the northeastern USA — among the lowest readings in this dataset, comparable to Easthampton MA (21.5 mg/L) and Colchester VT (19.5 mg/L). The Seymour watershed drains the Connecticut Highlands — Precambrian Totoket Granite (insoluble), Carboniferous New Haven Arkose (insoluble quartz-feldspar sandstone), and Precambrian Derby Amphibolite (insoluble). The entirely insoluble granite and arkose Highland basement contributes essentially no mineral hardness to the supply.

At 22.5 mg/L, Seymour's water is extremely soft — absolutely no scale forms, soap lathers exceptionally, and appliances maintain peak efficiency indefinitely. No descaling is ever needed. The PFAS level of 5.2 ppt warrants a certified drinking water filter — the Naugatuck Valley historic Brass Valley industrial corridor (Ansonia, Seymour, Derby — significant non-military PFAS legacy from metals processing and manufacturing), and the south-central Connecticut PFAS background contribute to Seymour's readings despite the pristine source water.