How hard is the water in Middlesex County, NJ?
4.7 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Middlesex County, NJ is 80 mg/L as calcium carbonate, which is 4.7 gpg. That is moderately hard on the USGS scale. It comes from 140 samples at 75 sites between 1990 and 2023, drawn from groundwater wells, which is what most taps and private wells in the county draw on.
How much it varies here
Half the sites came in between 1.9 and 10.5 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: high (how it is measured).
What to do next
At 4.7 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Middlesex County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on when a softener is not worth it.
From 0.3 to 93.5 gpg
The softest single sample on record in Middlesex County was 5 mg/L and the hardest 1,600 mg/L, a 320-fold gap. The top quarter of sites read above 10.5 gpg and the bottom quarter below 1.9 gpg.
Wells 4.7 gpg, rivers and lakes 2.9 gpg
140 groundwater samples from 75 wells put the median at 80 mg/L. 550 surface samples from 25 sites put it at 48.9 mg/L. In Middlesex County the wells come out 1.8 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 102 lb of salt a year (3 bags of 40 lb, about $18), and roughly 2,346 gallons of regeneration water. Installed, most units run $1,000 to $4,500; spread over 15 years with salt, that is about $118 a year.
Sizing at 4.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 282 | 24,000 | 34 lb |
| 2 | 564 | 24,000 | 69 lb |
| 4 | 1,128 | 24,000 | 137 lb |
| 6 | 1,692 | 24,000 | 206 lb |
Middlesex County against the rest of New Jersey
Among the 21 New Jersey counties with data, Middlesex County is number 13 of 21 counting from the hardest. Across the whole country it is harder than 29% of counties.
Softest in New Jersey: Ocean County at 0.8 gpg. Hardest: Hudson County at 17.2 gpg. Closest to Middlesex County: Salem County (5), Monmouth County (3.2), Cape May County (2.8).