Brooklyn Heights Water Hardness & Quality Report (2026)

The New York City Department of Environmental Protection (DEP) manages the water supply for Brooklyn Heights, serving all of New York City including Kings County (Brooklyn). Water is sourced from 19 reservoirs and three controlled lakes across the Catskill/Delaware and Croton watersheds upstate, delivered via aqueducts to distribution points. The Catskill/Delaware system contributes approximately 90% of supply from reservoirs including Ashokan, Schoharie, Rondout, and Delaware; the Croton system supplements from New Croton Lake and others. Treatment occurs at the Hillview Reservoir blending facility with chlorination at multiple points; UV disinfection is applied, and no filtration is required due to protected watershed quality.

The Catskill/Delaware Watershed spans 1,600 square miles across Ulster, Greene, Delaware, and Schoharie counties, featuring predominantly siliceous metamorphic and igneous rocks — the Fordham Gneiss (Precambrian) and Hamilton Group shales (Devonian) — which yield very soft water with minimal mineral dissolution. The Croton Watershed in Putnam and Westchester counties includes more varied Paleozoic formations such as the Manhattan Schist and Inwood Marble (Cambrian–Ordovician), contributing moderately mineralised water. Blending produces the soft 30.8 mg/L supply delivered to Brooklyn Heights, shaped by limited carbonate rock exposure and glacial till influences on surface runoff chemistry.

With a soft supply, scale buildup in kettles, dishwashers, and water heaters is moderate over time; showers and faucets may develop some limescale and laundry may require slightly more detergent. Weekly vinegar soaks for showerheads and regular descaling of coffee makers are practical maintenance steps. A water softener is unlikely to be needed for most households at this hardness level. NYC DEP maintains a pH of 7.0–8.0 for corrosion control; the system complies with the EPA Lead and Copper Rule through pipe replacement programs. No PFAS exceedances reported in recent DEP reports, with trace GenX and PFOS detected but below health advisories. Fluoride is adjusted to 0.7 mg/L and chlorination residuals are maintained at 0.5–1.0 mg/L.