Newark Water Hardness & Quality Report (2026)

Newark's water is supplied by the City of Newark Division of Water and Sewer Utilities, drawing from a reservoir system in the New Jersey Highlands northwest of the city. The primary sources are the Pequannock Watershed reservoirs — including Oak Ridge Reservoir, Echo Lake, Macopin Reservoir, and the Clinton Reservoir — and the Wanaque Reservoir system on the Wanaque River in Passaic County. These reservoirs collect precipitation draining the New Jersey Highlands, a rugged upland area of exposed Precambrian crystalline rock. Newark's water system is one of the oldest large municipal systems in New Jersey, and has been the subject of significant public attention following the discovery of elevated lead levels in service lines and home plumbing — a legacy of pre-1986 lead pipe infrastructure throughout the city's older housing stock.

Newark's moderately soft water at 102.5 mg/L reflects the Precambrian crystalline geology of the Highlands source watershed. The Pequannock and Wanaque drainages collect runoff from the New Jersey Highlands Province — underlain by Precambrian Losee Gneiss, Byram Intrusive Suite granite and granodiorite, and Grenville-age metamorphic complex rocks — which are silicate-dominated and resistant to carbonate dissolution. The Highlands Province is geologically analogous to the Hudson Highlands and Catskill region of New York, producing similarly soft water with minimal dissolved minerals. Some modest carbonate contribution enters from Ordovician limestone and dolomite formations exposed in the adjacent Valley and Ridge terrain to the northwest.

Newark's moderately soft water is not the primary water quality concern for residents — the city's well-documented lead service line problem is far more significant. Newark conducted an aggressive lead pipe replacement program beginning in 2019, and running the cold tap for 30–60 seconds before drawing drinking water, or using an NSF/ANSI 53-certified lead-reducing filter, remains the most important water safety practice for Newark residents in older buildings. On the hardness dimension, soap and appliances perform well, scale buildup is slow, and no descaling routine is necessary for most households.