Paterson Water Hardness & Quality Report (2026)

Paterson, New Jersey receives its municipal water supply from the Passaic Valley Water Commission (PVWC), sourcing from the Wanaque Reservoir and Monksville Reservoir — large surface water impoundments in Passaic and Bergen Counties in the New Jersey Highlands. The PVWC operates the Wanaque system as the primary supply for Paterson and numerous other northern New Jersey municipalities. Raw water is treated at the Wanaque Treatment Plant and the Haworth Treatment Plant before distribution throughout Passaic County. Water hardness in Paterson measures 141.5 mg/L — classified as moderately hard.

Paterson's moderate hardness reflects the geological diversity of the New Jersey Highlands and Piedmont watershed draining into the Wanaque system. The Highlands terrain comprises Proterozoic gneiss and schist (calcium-poor crystalline basement rocks) combined with the Cambrian Kittatinny Limestone belt along the ridge crests — a sequence of marble and calcareous metasediments that contribute dissolved calcium bicarbonate to drainage. Wanaque reservoir waters also receive runoff crossing the Jurassic basalt Watchung Ridges of the Newark Basin Piedmont, whose minerals add further hardness. The combined watershed produces a moderately hard finished supply that reflects the transition zone between the soft Highlands crystallines and the more calcareous Piedmont and limestone belts.

At 141.5 mg/L, Paterson residents encounter regular scale build-up on faucet aerators, showerheads, and inside kettles over time — monthly descaling with citric acid keeps fixtures performing well. Dishwashers produce better glassware with rinse-aid, and water heaters benefit from annual inspection for element scale. Passaic Valley Water Commission consistently delivers water meeting all New Jersey DEP and EPA Safe Drinking Water Act requirements throughout its northern New Jersey service area.