How hard is the water in Harper County, OK?
28.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Harper County, OK is 494 mg/L as calcium carbonate, which is 28.9 gpg. That is very hard on the USGS scale. It comes from 447 samples at 20 sites between 1990 and 2024, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 16.3 and 52.6 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 28.9 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 12.9 to 127.9 gpg
The softest single sample on record in Harper County was 220 mg/L and the hardest 2,188.9 mg/L, a 10-fold gap. The top quarter of sites read above 52.6 gpg and the bottom quarter below 16.3 gpg.
What a softener would cost to run
For a household of 3, a 40,000-grain unit covers a week between regenerations. Expect about 631 lb of salt a year (16 bags of 40 lb, about $114), 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 $214 a year.
Sizing at 28.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,734 | 24,000 | 211 lb |
| 2 | 3,468 | 32,000 | 422 lb |
| 4 | 6,936 | 64,000 | 844 lb |
| 6 | 10,404 | 80,000 | 1,266 lb |
Harper County against the rest of Oklahoma
Among the 77 Oklahoma counties with data, Harper County is number 17 of 77 counting from the hardest. Across the whole country it is harder than 94% of counties.
Softest in Oklahoma: McCurtain County at 0.8 gpg. Hardest: Greer County at 125 gpg. Closest to Harper County: Stephens County (28.7), Roger Mills County (29.5), Blaine County (26.3).