How hard is the water in Franklin County, MO?
24 grains per gallon
A softener will pay its way here.
The median hardness measured in Franklin County, MO is 410 mg/L as calcium carbonate, which is 24 gpg. That is very hard on the USGS scale. It comes from 59 samples at 23 sites between 1990 and 2023, 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 14.5 and 31 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 24 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 9.3 to 99.9 gpg
The softest single sample on record in Franklin County was 160 mg/L and the hardest 1,710 mg/L, an 11-fold gap. The top quarter of sites read above 31 gpg and the bottom quarter below 14.5 gpg.
Wells 24 gpg, rivers and lakes 8.1 gpg
59 groundwater samples from 23 wells put the median at 410 mg/L. 157 surface samples from 17 sites put it at 138 mg/L. In Franklin County the wells come out 15.9 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 32,000-grain unit covers a week between regenerations. Expect about 523 lb of salt a year (14 bags of 40 lb, about $94), 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 $194 a year.
Sizing at 24 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,440 | 24,000 | 175 lb |
| 2 | 2,880 | 24,000 | 350 lb |
| 4 | 5,760 | 48,000 | 701 lb |
| 6 | 8,640 | 64,000 | 1,051 lb |
Franklin County against the rest of Missouri
Among the 110 Missouri counties with data, Franklin County is number 8 of 110 counting from the hardest. Across the whole country it is harder than 91% of counties.
Softest in Missouri: Livingston County at 4.1 gpg. Hardest: Reynolds County at 96.7 gpg. Closest to Franklin County: Boone County (24), Henry County (21.4), Jackson County (26.9).