Parsippany Water Hardness & Quality Report (2026)

Parsippany–Troy Hills Township, New Jersey, in Morris County — a major New Jersey corporate headquarters community (Wyndham Hotels, Avis Budget Group, Zoetis, Honeywell International's former NJ campus), one of the largest townships in New Jersey, known as the 'Headquarters Capital of New Jersey' — draws its municipal water supply from the Rockaway River (Boonton Reservoir) and Passaic River via New Jersey American Water (NJAW) Morris District. Water hardness in Parsippany measures 139 mg/L — classified as moderately hard.

Parsippany's moderate hardness reflects the Morris County Rockaway River–Boonton watershed's New Jersey Highlands geology. The Rockaway River above Boonton Reservoir drains: the New Jersey Highlands (Proterozoic Byram Intrusive Suite granodiorite and gneiss — calcium-poor crystalline Precambrian terrain); the Franklin Marble (Proterozoic calcareous marble of the New Jersey Highlands — the famous zinc ore host at Franklin, some calcareous contribution); and the Ordovician–Devonian calcareous limestone of the Highlands transition zone. The New Jersey Highlands calcareous marble and crystalline terrain produce the moderate 139 mg/L — consistent with the Morris County suburban supply pattern.

At 139 mg/L, Parsippany residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. New Jersey American Water consistently delivers water meeting all New Jersey DEP and EPA Safe Drinking Water Act requirements.