How hard is the water in Benton County, MO?
16.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Benton County, MO is 289 mg/L as calcium carbonate, which is 16.9 gpg. That is very hard on the USGS scale. It comes from 52 samples at 8 sites between 1993 and 2022, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 12.3 and 17.8 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: medium (how it is measured).
What to do next
At 16.9 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 9.8 to 19.5 gpg
The softest single sample on record in Benton County was 168 mg/L and the hardest 334 mg/L, a 2-fold gap. The top quarter of sites read above 17.8 gpg and the bottom quarter below 12.3 gpg.
Wells 19.3 gpg, rivers and lakes 12.4 gpg
3 groundwater samples from 3 wells put the median at 331 mg/L. 49 surface samples from 5 sites put it at 211.5 mg/L. In Benton County the wells come out 6.9 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 24,000-grain unit covers a week between regenerations. Expect about 369 lb of salt a year (10 bags of 40 lb, about $66), 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 $166 a year.
Sizing at 16.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,014 | 24,000 | 123 lb |
| 2 | 2,028 | 24,000 | 247 lb |
| 4 | 4,056 | 32,000 | 493 lb |
| 6 | 6,084 | 48,000 | 740 lb |
Benton County against the rest of Missouri
Among the 110 Missouri counties with data, Benton County is number 11 of 110 counting from the hardest. Across the whole country it is harder than 75% of counties.
Softest in Missouri: Livingston County at 4.1 gpg. Hardest: Reynolds County at 96.7 gpg. Closest to Benton County: Maries County (16.6), St. Charles County (17.2), Cape Girardeau County (16.4).