How hard is the water in Mayes County, OK?

5.9 grains per gallon

Optional: a softener helps, but plenty of homes skip it.

The median hardness measured in Mayes County, OK is 102 mg/L as calcium carbonate, which is 5.9 gpg. That is moderately hard on the USGS scale. It comes from 972 samples at 25 sites between 2000 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 4.7 and 6.6 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 5.9 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one.

More on when a softener is not worth it.

From 3.6 to 9.6 gpg

The softest single sample on record in Mayes County was 62 mg/L and the hardest 164 mg/L, a 3-fold gap. The top quarter of sites read above 6.6 gpg and the bottom quarter below 4.7 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 130 lb of salt a year (4 bags of 40 lb, about $23), 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 $123 a year.

Sizing at 5.9 gpg

Mayes County against the rest of Oklahoma

Among the 77 Oklahoma counties with data, Mayes County is number 68 of 77 counting from the hardest. Across the whole country it is harder than 35% of counties.

Softest in Oklahoma: McCurtain County at 0.8 gpg. Hardest: Greer County at 125 gpg. Closest to Mayes County: Adair County (6), Wagoner County (6.6), Sequoyah County (5.3).