Brooklyn Water Hardness & Quality Report (2026)

The New York City Department of Environmental Protection (DEP) supplies water to Brooklyn as part of the citywide system serving over 8 million residents across five boroughs. Brooklyn receives a blend from the Catskill/Delaware watershed (via Hillview Reservoir) and the Croton watershed (via Croton Lake). Primary treatment occurs at the Hillview and Croton facilities, with disinfection via chlorination and UV. Distribution covers Kings County through the Delaware Aqueduct and New Croton Aqueduct.

The Catskill/Delaware Watershed spans 2,000 square miles in the Catskills and Delaware River basin, featuring Devonian shales, sandstones, and metamorphic rocks that yield soft water through low mineral leaching. The Croton Watershed, at 375 square miles, involves Hudson Highlands gneiss and schist formations from the Paleozoic era, imparting moderately mineralised character through higher calcium and magnesium dissolution. No major aquifers are tapped; surface reservoirs dominate, with rainfall dilution further softening the blended supply.

Moderately soft water produces minimal scale buildup on fixtures, reducing spots on glassware and faucets compared to harder supplies. Dishwashers and water heaters see low maintenance needs; efficient soap lathering reduces detergent use, and laundry stays brighter. A water softener is unnecessary citywide, though optional in Croton-heavy zones; regular vinegar rinses suffice for any light residue. NYC DEP meets lead and copper rules via corrosion control, though older building pipes pose localized risks. No widespread PFAS exceedances reported; low-level disinfection byproducts (TTHMs, haloacetic acids) remain below EPA limits. Treatment includes UV disinfection at the Delaware plant, chlorination throughout, and fluoridation.