Water hardness in Summit, New Jersey

The published hardness reading for Summit is 167 mg/L, equal to 9.8 grains per gallon — hard water. Short Hills Service System reports it in NJ American Water CCR (2025 CCR (PWS ID NJ0712001)); Summit sits inside that service area in Union County.

Expect visible scale on fixtures, spotting on dishes, and shortened service life on water heaters that are never flushed. Ion-exchange softening is generally worth considering at this level.

Summit does not treat its own water: it buys from Short Hills System, which reports hardness of 9.8 gpg across its whole service area. That is why 5 other New Jersey municipalities publish the same number.

See the full Short Hills System water quality report for the complete panel — sodium, chloride, sulfate, fluoride, manganese, iron, pH and total dissolved solids — plus every other town on the system.

At 9.8 gpg, Summit sits in the hard band. An ion-exchange softener is generally the better fit than a conditioner at this level, because it removes the calcium and magnesium rather than converting them, which is what prevents scale in the water heater as well as on fixtures. A conditioner still helps if brine discharge is restricted or there is no drain nearby.

Where Summit housing predates modern plumbing, scale costs more: galvanised and narrow copper runs lose bore as deposits build, while PEX and wider copper tolerate the same water for longer. The age of the pipe, not only the number, sets the urgency.

Hardness in Summit is not a fixed number through the year — a utility figure is an annual average, and demand, source switching and temperature all shift it. If a reading at your tap differs from 9.8 gpg, the season it was taken in explains part of the gap.

Run the arithmetic before committing: softening at this level carries salt, water and servicing costs every year, against slower element scaling and less detergent. Below the hard band that trade rarely pays back on utility alone; above it, the heater replacement usually decides it.

For the mechanics behind that, what hard water actually is covers the units and scale chemistry, and the Learn hub compares softeners against conditioners in detail.

Short Hills System reports sodium of 5 to 139 ppm — the top of that range, about 139 ppm, is already above the 20 mg/L level the EPA suggests as a guide for people on a physician-ordered 500 mg/day sodium restriction, before any treatment is added at the house.

That matters if softening is on the table in Summit, because ion exchange trades calcium and magnesium for sodium at roughly 8 mg/L for every grain per gallon removed — on 9.8 gpg that is an added ~78 mg/L on top of what the utility already delivers. Households watching sodium usually leave the kitchen cold tap unsoftened or fit potassium chloride instead.

For the full breakdown, read how much sodium a softener actually adds, which sets out the sources behind it.