How hard is the water in Loudoun County, VA?
9 grains per gallon
A softener is worth it here.
The median hardness measured in Loudoun County, VA is 154 mg/L as calcium carbonate, which is 9 gpg. That is hard on the USGS scale. It comes from 17 samples at 13 sites between 1993 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 7.9 and 12.2 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: medium (how it is measured).
What to do next
At 9 gpg a softener is worth getting, mainly to protect the water heater and cut soap use. Get at least two quotes, ask each installer what grain capacity they are fitting, and check it against the sizing table below. Because Loudoun County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on sizing a softener for your household.
From 4.7 to 13.8 gpg
The softest single sample on record in Loudoun County was 80.2 mg/L and the hardest 237 mg/L, a 3-fold gap. The top quarter of sites read above 12.2 gpg and the bottom quarter below 7.9 gpg.
Wells 9 gpg, rivers and lakes 3.8 gpg
17 groundwater samples from 13 wells put the median at 153.5 mg/L. 648 surface samples from 30 sites put it at 65.9 mg/L. In Loudoun County the wells come out 5.2 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 24,000-grain unit covers a week between regenerations. Expect about 196 lb of salt a year (5 bags of 40 lb, about $35), 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 $135 a year.
Sizing at 9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 540 | 24,000 | 66 lb |
| 2 | 1,080 | 24,000 | 131 lb |
| 4 | 2,160 | 24,000 | 263 lb |
| 6 | 3,240 | 24,000 | 394 lb |
Loudoun County against the rest of Virginia
Among the 126 Virginia counties with data, Loudoun County is number 22 of 126 counting from the hardest. Across the whole country it is harder than 47% of counties.
Softest in Virginia: Isle of Wight County at 0.4 gpg. Hardest: Clarke County at 20.1 gpg. Closest to Loudoun County: Russell County (9.1), Scott County (9.3), Salem city (8.6).