Summit Water Hardness & Quality Report (2026)

Summit, New Jersey, in Union County — one of New Jersey's most affluent communities, a well-preserved Victorian-era city on the Watchung Ridge with an exceptional Main Street and consistent ranking among the state's best places to live — receives its municipal water from New Jersey American Water or the Elizabethtown Water Company, which draws from the Raritan River Basin reservoir system or connections to the Lake Passaic Wanaque Reservoir network in northern New Jersey. Summit's elevated Watchung Ridge position means its distribution system must serve the hillside residential neighborhoods through pumped pressure zones.

The moderately hard 146 mg/L hardness and TDS of 349 mg/L reflect the north-central New Jersey watershed blend of Triassic Piedmont and Precambrian Highlands geology. The supply drains the New Jersey Piedmont's Triassic Newark Basin (Brunswick and Passaic Formation redbeds), the Precambrian Reading Prong Highlands gneiss (Lower Passaic watershed), and the Raritan-Bound Brook corridor's mixed geology — producing a moderately hard, moderate-TDS Raritan Basin finished supply consistent throughout the Union County-Somerset County New Jersey American Water service territory.

At 146 mg/L, Summit's water is moderately hard — scale builds in kettles and coffee machines over months, dishwashers benefit from rinse aid, and bathroom fixtures develop calcium deposits. Quarterly descaling of heating appliances is the appropriate schedule. The critically elevated PFAS level of 11.1 ppt requires urgent attention — Summit's Union County position in the densely industrialized northern New Jersey corridor, the Raritan River basin's documented PFAS contamination from the Bound Brook-Somerville pharmaceutical and chemical manufacturing zone, and New Jersey's pervasive PFAS legacy from its enormous industrial chemical legacy produce one of the state's more serious municipal PFAS readings. A certified reverse osmosis drinking water filter is strongly recommended for all drinking and cooking water in Summit.