How hard is the water in McClain County, OK?
24.2 grains per gallon
A softener will pay its way here.
The median hardness measured in McClain County, OK is 414 mg/L as calcium carbonate, which is 24.2 gpg. That is very hard on the USGS scale. It comes from 212 samples at 10 sites between 1990 and 2025, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 23 and 25.1 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 24.2 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 22.2 to 27.9 gpg
The softest single sample on record in McClain County was 380 mg/L and the hardest 478 mg/L, a 1-fold gap. The top quarter of sites read above 25.1 gpg and the bottom quarter below 23 gpg.
What a softener would cost to run
For a household of 3, a 32,000-grain unit covers a week between regenerations. Expect about 528 lb of salt a year (14 bags of 40 lb, about $95), 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 $195 a year.
Sizing at 24.2 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,452 | 24,000 | 177 lb |
| 2 | 2,904 | 24,000 | 353 lb |
| 4 | 5,808 | 48,000 | 707 lb |
| 6 | 8,712 | 64,000 | 1,060 lb |
McClain County against the rest of Oklahoma
Among the 77 Oklahoma counties with data, McClain County is number 21 of 77 counting from the hardest. Across the whole country it is harder than 91% of counties.
Softest in Oklahoma: McCurtain County at 0.8 gpg. Hardest: Greer County at 125 gpg. Closest to McClain County: Garfield County (23.6), Canadian County (25.9), Blaine County (26.3).