Highland Park Water Hardness & Quality Report (2026)

The Highland Park Water Department supplies water to approximately 14,000 residents in Highland Park, Edison, and New Brunswick. Their primary source is the Raritan River, accessed via the Delaware and Raritan Canal intake. Water is treated at facilities managed by the Raritan-Millstone Water Supply System in partnership with Middlesex Water Company. Conventional treatment processes, including coagulation, sedimentation, filtration, and disinfection, are employed at plants such as the Edgar Springs facility. The extensive Raritan River watershed, covering 1,100 square miles, flows through varied geology within the Newark Basin.

This region's geology features Triassic sedimentary rocks, specifically the Stockton and Lockatong Formations, which are red beds containing calcium-rich minerals. Diabase intrusions and overlying Quaternary alluvium also influence the water's mineral content as it moves through fractured bedrock. The Raritan River's chemistry is shaped by upstream limestone outcrops, leading to a supply that is characteristically hard. Karst topography in the Passaic Formation can further increase mineral pickup, contributing to the water's mineralized profile.

Homeowners in Highland Park may notice scale buildup on faucets, in kettles, and inside dishwashers due to the water's hardness. Appliances like water heaters and washing machines can experience reduced efficiency, sometimes by up to 30%, and a shortened lifespan. This is particularly true for hot water systems where minerals precipitate more readily. To combat these effects, regular descaling with vinegar, installing sediment filters, and considering a water softener are practical steps. These measures can extend appliance life and improve the lathering of soaps for bathing and laundry.