Forest Hills Water Hardness & Quality Report (2026)

Forest Hills, NY receives drinking water from the New York City Department of Environmental Protection (DEP), supplying over 1 billion gallons daily to 9 million residents across Queens County and the five boroughs. The supply originates from protected upstate reservoirs: the Croton System (including New Croton Lake and Cross River Reservoir), the Catskill System (including Ashokan Reservoir and Schoharie Reservoir), and the Delaware System (including Rondout Reservoir and Pepacton Reservoir). Water is treated at the Catskill/Delaware Ultraviolet (UV) Disinfection Facility at Wards Island and the Croton UV facility, distributed through citywide aqueducts and tunnels.

The NYC watersheds span 2,000 square miles in the Catskill Mountains and Hudson Valley, underlain by ancient metamorphic and igneous rocks including Fordham Gneiss and Manhattan Schist from the Grenville Province (over 1 billion years old). These non-carbonate formations resist chemical weathering and contribute minimal dissolved calcium and magnesium. Surface water dominance over groundwater minimizes interaction with mineral-rich soils, preserving the naturally soft character despite mixed watershed inputs.

Forest Hills' supply may cause minor scale buildup in dishwashers, coffee makers, and water heaters over time, with reduced soap lathering and spotty dishes. Monthly vinegar descaling is recommended; a water softener is optional but beneficial for households noticing dry skin or preferring improved lathering, especially during Croton-blended periods. NYC water maintains pH 6.5–8.5 in full EPA compliance with robust lead/copper rule adherence via corrosion control and pipe replacement programs; no PFAS exceedances reported in recent DEP monitoring. Treatment involves UV disinfection, ozonation, chlorination, and fluoridation (0.7 mg/L).