How hard is the water in Northumberland County, PA?
4.6 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Northumberland County, PA is 78 mg/L as calcium carbonate, which is 4.6 gpg. That is moderately hard on the USGS scale. It comes from 156 samples at 86 sites between 1990 and 2026, 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 3.2 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 4.6 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 Northumberland 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 0.7 to 38.3 gpg
The softest single sample on record in Northumberland County was 12.6 mg/L and the hardest 655.5 mg/L, a 52-fold gap. The top quarter of sites read above 10.5 gpg and the bottom quarter below 3.2 gpg.
Wells 4.6 gpg, rivers and lakes 6.1 gpg
156 groundwater samples from 86 wells put the median at 78.4 mg/L. 2,130 surface samples from 92 sites put it at 104 mg/L. In Northumberland County the rivers and lakes come out 1.5 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. 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 100 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 4.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 276 | 24,000 | 34 lb |
| 2 | 552 | 24,000 | 67 lb |
| 4 | 1,104 | 24,000 | 134 lb |
| 6 | 1,656 | 24,000 | 201 lb |
Northumberland County against the rest of Pennsylvania
Among the 67 Pennsylvania counties with data, Northumberland County is number 48 of 67 counting from the hardest. Across the whole country it is harder than 29% of counties.
Softest in Pennsylvania: Cameron County at 1.4 gpg. Hardest: Clarion County at 68.2 gpg. Closest to Northumberland County: Northampton County (4.5), York County (4.6), Wayne County (4.4).