Edison Water Hardness & Quality Report (2026)

Edison Township, New Jersey, in Middlesex County — one of New Jersey's largest townships — receives its water from two primary providers: Middlesex Water Company (serving a large portion of Edison) and New Jersey American Water (serving Edison's Arthur Kill and Raritan River industrial corridor zones). Middlesex Water sources from the Raritan River via the Bound Brook treatment plant and from Cretaceous coastal plain aquifer wells (Raritan Formation) in Middlesex County. New Jersey American Water supplements with additional Raritan Basin surface water. Water hardness measures 154.5 mg/L — classified as hard.

Edison's hard supply reflects the dual influence of Raritan River water and Middlesex County Cretaceous Raritan Formation aquifer groundwater. The Raritan River drains the central New Jersey watershed: Precambrian Highlands gneiss (calcium-poor) in the upper watershed (Somerset Hills), but crossing the Triassic Newark Basin (Brunswick Formation red shale — contains calcite cement and calcareous fragments) in the middle reach, contributing moderate calcium to river chemistry. The Cretaceous Raritan Formation coastal plain aquifer — a deep sand aquifer beneath Middlesex County — dissolves calcium from calcareous marine sand cement during extended subsurface residence, contributing additional hardness to the blended supply.

At 154.5 mg/L, Edison residents face moderate to significant scale challenges in household use. Faucet aerators and showerheads develop deposits within weeks — monthly descaling with citric acid solution is standard maintenance. Dishwashers require rinse-aid for acceptable glassware results, and water heaters benefit from annual inspection. Middlesex Water Company and New Jersey American Water consistently deliver water meeting all NJDEP and EPA Safe Drinking Water Act requirements.