South River Water Hardness & Quality Report (2026)

South River, New Jersey, in Middlesex County — a Middlesex County borough adjacent to Old Bridge and East Brunswick on the South River (a tributary of the Raritan) in central New Jersey — receives its municipal water from New Jersey American Water, drawing from the Raritan River system (Middlesex County) through the NJAW Raritan treatment plant.

The moderately hard 130 mg/L hardness and TDS of 294.2 mg/L reflect the central New Jersey Raritan River supply's mixed Triassic-Piedmont carbonate character. The Raritan River at Middlesex County drains the New Jersey Piedmont — Triassic Brunswick Formation (calcareous red shale — the primary New Jersey river hardness contributor), Cambrian Lamington Dolomite (high purity carbonate), and Precambrian Wissahickon Formation (metamorphic — moderately insoluble). The Triassic calcareous Newark Basin contribution produces the moderately hard central New Jersey supply.

At 130 mg/L, South River's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 10.2 ppt warrants a certified reverse osmosis drinking water filter — the Middlesex County central New Jersey industrial corridor (the Raritan Center industrial park, New Brunswick chemical and pharmaceutical manufacturing), and the New Jersey PFAS complex from military and industrial sources contribute to South River's very elevated readings.