Uniondale Water Hardness & Quality Report (2026)

Uniondale, NY receives drinking water from the Hempstead Town Water Department, serving Nassau County on western Long Island. The supply is entirely groundwater drawn from local wells tapping the Upper Glacial and Magothy aquifers — part of Long Island's sole-source aquifer system recharged by precipitation percolating through sandy soils. There are no surface water treatment plants; water is treated at wellhead facilities for disinfection and corrosion control before distribution to approximately 20,000 residents in Uniondale and interconnected districts including East Meadow and Levittown.

The groundwater originates within Long Island's sole-source aquifer system. The geology features Quaternary glacial sands and gravels of the Upper Glacial aquifer overlying Cretaceous formations — the Magothy and Raritan — consisting of unconsolidated sands and clays of the Raritan Formation. This non-calcareous, non-carbonate geology yields naturally soft water with low dissolved calcium and magnesium and minimal dissolved solids, distinguishing it from harder inland or upstate supplies influenced by limestone bedrock.

As soft water, Uniondale's supply produces minimal scale buildup, sparing appliances including water heaters, dishwashers, and coffee makers from calcification. Soap lathers easily, reducing detergent usage. Soft water may accelerate pipe corrosion — monitor for pinhole leaks and consider phosphate inhibitors if needed. A water softener is not recommended and could exacerbate corrosion; routine filter changes and vinegar rinses for minor spots are sufficient. Tap water meets all EPA standards; treatment includes chlorination for disinfection and fluoride addition where required; iron and manganese from aquifers are monitored but remain below limits.