How hard is the water in Grant County, OK?
21.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Grant County, OK is 370 mg/L as calcium carbonate, which is 21.6 gpg. That is very hard on the USGS scale. It comes from 283 samples at 18 sites between 2000 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 16.8 and 26.8 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 21.6 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 16.4 to 31.5 gpg
The softest single sample on record in Grant County was 280 mg/L and the hardest 540 mg/L, a 2-fold gap. The top quarter of sites read above 26.8 gpg and the bottom quarter below 16.8 gpg.
Wells 31 gpg, rivers and lakes 20.4 gpg
1 groundwater samples from 1 wells put the median at 531 mg/L. 282 surface samples from 17 sites put it at 350 mg/L. In Grant County the wells come out 10.6 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 472 lb of salt a year (12 bags of 40 lb, about $85), 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 $185 a year.
Sizing at 21.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,296 | 24,000 | 158 lb |
| 2 | 2,592 | 24,000 | 315 lb |
| 4 | 5,184 | 40,000 | 631 lb |
| 6 | 7,776 | 64,000 | 946 lb |
Grant County against the rest of Oklahoma
Among the 77 Oklahoma counties with data, Grant County is number 23 of 77 counting from the hardest. Across the whole country it is harder than 87% of counties.
Softest in Oklahoma: McCurtain County at 0.8 gpg. Hardest: Greer County at 125 gpg. Closest to Grant County: Pontotoc County (20.5), Johnston County (20.3), Garfield County (23.6).