How hard is the water in Allegheny County, PA?
22.4 grains per gallon
A softener will pay its way here.
The median hardness measured in Allegheny County, PA is 383 mg/L as calcium carbonate, which is 22.4 gpg. That is very hard on the USGS scale. It comes from 34 samples at 11 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 19 and 43.6 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: high (how it is measured).
What to do next
At 22.4 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water.
More on sizing a softener for your household.
From 7.2 to 144.9 gpg
The softest single sample on record in Allegheny County was 124 mg/L and the hardest 2,480 mg/L, a 20-fold gap. The top quarter of sites read above 43.6 gpg and the bottom quarter below 19 gpg.
Wells 22.4 gpg, rivers and lakes 14.5 gpg
34 groundwater samples from 11 wells put the median at 383 mg/L. 2,502 surface samples from 92 sites put it at 247.5 mg/L. In Allegheny County the wells come out 7.9 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 32,000-grain unit covers a week between regenerations. Expect about 489 lb of salt a year (13 bags of 40 lb, about $88), 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 $188 a year.
Sizing at 22.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,344 | 24,000 | 164 lb |
| 2 | 2,688 | 24,000 | 327 lb |
| 4 | 5,376 | 40,000 | 654 lb |
| 6 | 8,064 | 64,000 | 981 lb |
Allegheny County against the rest of Pennsylvania
Among the 67 Pennsylvania counties with data, Allegheny County is number 8 of 67 counting from the hardest. Across the whole country it is harder than 88% of counties.
Softest in Pennsylvania: Cameron County at 1.4 gpg. Hardest: Clarion County at 68.2 gpg. Closest to Allegheny County: Blair County (21.3), Westmoreland County (25), Mifflin County (19.5).