How hard is the water in Comanche County, OK?
10 grains per gallon
A softener is worth it here.
The median hardness measured in Comanche County, OK is 171 mg/L as calcium carbonate, which is 10 gpg. That is hard on the USGS scale. It comes from 147 samples at 17 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 8.2 and 15.9 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 10 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 Comanche 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 0.3 to 42.1 gpg
The softest single sample on record in Comanche County was 5.4 mg/L and the hardest 720 mg/L, a 133-fold gap. The top quarter of sites read above 15.9 gpg and the bottom quarter below 8.2 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 0.3 gpg, rivers and lakes 11.9 gpg
1 groundwater samples from 1 wells put the median at 5.4 mg/L. 146 surface samples from 16 sites put it at 203 mg/L. In Comanche County the rivers and lakes come out 11.6 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. A utility here that draws from the aquifer 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 218 lb of salt a year (6 bags of 40 lb, about $39), 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 $139 a year.
Sizing at 10 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 600 | 24,000 | 73 lb |
| 2 | 1,200 | 24,000 | 146 lb |
| 4 | 2,400 | 24,000 | 292 lb |
| 6 | 3,600 | 32,000 | 438 lb |
Comanche County against the rest of Oklahoma
Among the 77 Oklahoma counties with data, Comanche County is number 54 of 77 counting from the hardest. Across the whole country it is harder than 51% of counties.
Softest in Oklahoma: McCurtain County at 0.8 gpg. Hardest: Greer County at 125 gpg. Closest to Comanche County: Okmulgee County (9.7), Caddo County (10.5), Okfuskee County (9.4).