How hard is the water in Story County, IA?
21.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Story County, IA is 370 mg/L as calcium carbonate, which is 21.6 gpg. That is very hard on the USGS scale. It comes from 28 samples at 13 sites between 1990 and 2013, 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 19.2 and 22.7 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 21.6 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 16.4 to 28.2 gpg
The softest single sample on record in Story County was 280 mg/L and the hardest 482 mg/L, a 2-fold gap. The top quarter of sites read above 22.7 gpg and the bottom quarter below 19.2 gpg.
Wells 21.6 gpg, rivers and lakes 19.7 gpg
28 groundwater samples from 13 wells put the median at 370 mg/L. 2 surface samples from 2 sites put it at 338 mg/L. In Story County the wells come out 1.9 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 32,000-grain unit covers a week between regenerations. Expect about 472 lb of salt a year (12 bags of 40 lb, about $85), 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 $185 a year.
Sizing at 21.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,296 | 24,000 | 158 lb |
| 2 | 2,592 | 24,000 | 315 lb |
| 4 | 5,184 | 40,000 | 631 lb |
| 6 | 7,776 | 64,000 | 946 lb |
Story County against the rest of Iowa
Among the 93 Iowa counties with data, Story County is number 33 of 93 counting from the hardest. Across the whole country it is harder than 87% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Story County: Mills County (21.6), Polk County (21.6), Marshall County (21.2).