How hard is the water in Washington County, OK?
7.8 grains per gallon
A softener is worth it here.
The median hardness measured in Washington County, OK is 133 mg/L as calcium carbonate, which is 7.8 gpg. That is hard on the USGS scale. It comes from 162 samples at 10 sites between 1990 and 2018, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 5.9 and 11.1 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 7.8 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 Washington 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 5.5 to 14.3 gpg
The softest single sample on record in Washington County was 94.5 mg/L and the hardest 245 mg/L, a 3-fold gap. The top quarter of sites read above 11.1 gpg and the bottom quarter below 5.9 gpg.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 170 lb of salt a year (5 bags of 40 lb, about $31), 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 $131 a year.
Sizing at 7.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 468 | 24,000 | 57 lb |
| 2 | 936 | 24,000 | 114 lb |
| 4 | 1,872 | 24,000 | 228 lb |
| 6 | 2,808 | 24,000 | 342 lb |
Washington County against the rest of Oklahoma
Among the 77 Oklahoma counties with data, Washington County is number 61 of 77 counting from the hardest. Across the whole country it is harder than 42% of counties.
Softest in Oklahoma: McCurtain County at 0.8 gpg. Hardest: Greer County at 125 gpg. Closest to Washington County: Haskell County (7.7), Choctaw County (8), Coal County (7.3).