How hard is the water in Henry County, MO?
21.4 grains per gallon
A softener will pay its way here.
The median hardness measured in Henry County, MO is 367 mg/L as calcium carbonate, which is 21.4 gpg. That is very hard on the USGS scale. It comes from 215 samples at 19 sites between 1990 and 2026, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 12.1 and 44.4 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 21.4 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 7.5 to 134.4 gpg
The softest single sample on record in Henry County was 128 mg/L and the hardest 2,300 mg/L, an 18-fold gap. The top quarter of sites read above 44.4 gpg and the bottom quarter below 12.1 gpg.
Wells 12.6 gpg, rivers and lakes 21.6 gpg
2 groundwater samples from 2 wells put the median at 216 mg/L. 213 surface samples from 17 sites put it at 370.5 mg/L. In Henry County the rivers and lakes come out 9.0 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 32,000-grain unit covers a week between regenerations. Expect about 468 lb of salt a year (12 bags of 40 lb, about $84), 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 $184 a year.
Sizing at 21.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,284 | 24,000 | 156 lb |
| 2 | 2,568 | 24,000 | 312 lb |
| 4 | 5,136 | 40,000 | 625 lb |
| 6 | 7,704 | 64,000 | 937 lb |
Henry County against the rest of Missouri
Among the 110 Missouri counties with data, Henry County is number 9 of 110 counting from the hardest. Across the whole country it is harder than 87% of counties.
Softest in Missouri: Livingston County at 4.1 gpg. Hardest: Reynolds County at 96.7 gpg. Closest to Henry County: Franklin County (24), Boone County (24), St. Charles County (17.2).