Fairfield Water Hardness & Quality Report (2026)

Fairfield, Connecticut, in Fairfield County on Long Island Sound — one of Connecticut's most affluent suburban towns, home of Fairfield University and Sacred Heart University, and a major Metro North commuter community for New York City — draws its municipal water supply from the Saugatuck Reservoir and Hemlock Reservoir via Aquarion Water Company of Connecticut, treating Fairfield County watershed water for the Fairfield area. Water hardness in Fairfield measures 80.5 mg/L — classified as moderately soft.

Fairfield's moderate softness reflects the Saugatuck River watershed's southwest Connecticut crystalline geology. The Saugatuck River above the reservoir drains: the Proterozoic Grenville-age Housatonic Highlands gneiss and Lebanon Gneiss (calcium-poor Proterozoic crystalline basement of southwest Connecticut); some Ordovician–Silurian calcareous marble and quartzite of the Berkshire Highlands metamorphic sequence (minor calcareous contribution); and the Jurassic diabase dikes intruding the southwest Connecticut gneiss (calcium-poor). The dominant Proterozoic crystalline terrain of southwest Connecticut produces the moderately soft 80.5 mg/L.

With hardness at 80.5 mg/L, Fairfield residents enjoy moderately soft water with minimal scale challenges. Aquarion Water Company consistently delivers water meeting all Connecticut DEEP and EPA Safe Drinking Water Act requirements.