How hard is the water in St. Francis County, AR?
18.3 grains per gallon
A softener will pay its way here.
The median hardness measured in St. Francis County, AR is 313 mg/L as calcium carbonate, which is 18.3 gpg. That is very hard on the USGS scale. It comes from 8 samples at 8 sites between 1990 and 2026, drawn from groundwater wells, which is what most taps and private wells in the county draw on.
How much it varies here
Half the sites came in between 16.7 and 28.1 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: medium (how it is measured).
What to do next
At 18.3 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 0.1 to 37.3 gpg
The softest single sample on record in St. Francis County was 1.1 mg/L and the hardest 639 mg/L, a 581-fold gap. The top quarter of sites read above 28.1 gpg and the bottom quarter below 16.7 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 18.3 gpg, rivers and lakes 5.7 gpg
8 groundwater samples from 8 wells put the median at 312.5 mg/L. 833 surface samples from 10 sites put it at 98 mg/L. In St. Francis County the wells come out 12.6 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 399 lb of salt a year (10 bags of 40 lb, about $72), 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 $172 a year.
Sizing at 18.3 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,098 | 24,000 | 134 lb |
| 2 | 2,196 | 24,000 | 267 lb |
| 4 | 4,392 | 32,000 | 534 lb |
| 6 | 6,588 | 48,000 | 802 lb |
St. Francis County against the rest of Arkansas
Among the 75 Arkansas counties with data, St. Francis County is number 7 of 75 counting from the hardest. Across the whole country it is harder than 79% of counties.
Softest in Arkansas: Hempstead County at 0.1 gpg. Hardest: Prairie County at 23.9 gpg. Closest to St. Francis County: Poinsett County (18.4), Chicot County (17.3), Cross County (16.9).