White Plains Water Hardness & Quality Report (2026)

The City of White Plains Department of Public Works - Bureau of Utilities provides drinking water to approximately 60,000 residents across 10 square miles in Westchester County, New York. One hundred percent of the supply is purchased from the New York City Department of Environmental Protection (NYCDEP) via Westchester County Water District No. 1. Water is drawn exclusively from the Kensico Reservoir, an unfiltered surface water impoundment with no local treatment plants; distribution follows NYCDEP processing. An emergency interconnection exists to the Delaware Aqueduct at Shaft 22.

The Kensico Reservoir is a key terminal storage facility in the expansive New York City Watershed, encompassing over 2,000 square miles across the Catskill, Delaware, and Croton systems. Underlying catchment geology features resistant metamorphic bedrock — gneiss and schist — from Precambrian and early Paleozoic eras, including rocks of the Grenville Province and Fordham Gneiss formations, with thin glacial till and podzolic soils. The absence of significant limestone or dolomite aquifers results in a low-mineral, soft to moderately mineralised profile; watershed protection by NYCDEP includes regulated land use to preserve this pristine quality.

As a moderately mineralised supply, White Plains water promotes efficient soap lathering and reduced spotting on glassware, though thin scale may deposit in high-use fixtures over time. Kettles, coffee makers, and water heaters experience gradual buildup; routine vinegar descaling every 3–6 months suffices for most households, and whole-house softening is not typically recommended. NYCDEP treatment includes fluoridation, chlorination, pH adjustment with caustic soda, and orthophosphate corrosion control. Recent reports note 8 contaminants exceeding health guidelines including carcinogenic chromium-6; pH is typically 7.5–8.5; lead and copper rules are met via orthophosphate; PFAS monitoring shows low levels from protected reservoirs.