South Windsor Water Hardness & Quality Report (2026)

South Windsor, Connecticut, in Hartford County in the Connecticut River Valley north of Hartford, receives its municipal water from the Metropolitan District Commission (MDC), the regional water authority serving the greater Hartford area. The MDC draws primarily from Barkhamsted Reservoir on the West Branch Farmington River in the Litchfield Hills — one of the largest and most remote reservoir systems in Connecticut — along with Nepaug Reservoir and Compensating Reservoir as supplementary sources. This large reservoir complex provides water to Hartford and its ring suburbs including South Windsor.

The very soft 41 mg/L hardness and low TDS of 75.8 mg/L reflect the pristine character of the Farmington River's Connecticut Western Highlands watershed. Barkhamsted Reservoir collects water from a heavily forested, lightly developed watershed in the Litchfield Hills — an area of Precambrian gneiss, Paleozoic metasedimentary schist, and granite intrusions with no soluble carbonate minerals. Precipitation falling on these ancient crystalline terrains picks up virtually no calcium or magnesium as it drains into the reservoir, producing one of the softest municipal water supplies in the Connecticut River Valley.

At 41 mg/L, South Windsor's water is very soft — excellent for appliances and comfortable for all household uses. Soap lathers readily, appliances remain scale-free for six months or longer, and glassware emerges spotless from the dishwasher. The characteristic concern for soft New England water is its mild corrosive tendency — very soft water with low TDS can leach trace metals from older copper or lead-tin solder plumbing over time. Residents in pre-1986 homes should flush cold taps first thing in the morning. The PFAS level of 6.8 ppt warrants a certified drinking water filter for daily tap water consumption.