How hard is the water in Grant County, OR?
4.8 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Grant County, OR is 82 mg/L as calcium carbonate, which is 4.8 gpg. That is moderately hard on the USGS scale. It comes from 188 samples at 12 sites between 2010 and 2025, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 3.3 and 6.7 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: high (how it is measured).
What to do next
At 4.8 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Grant County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on when a softener is not worth it.
From 0.7 to 8.5 gpg
The softest single sample on record in Grant County was 11.3 mg/L and the hardest 145 mg/L, a 13-fold gap. The top quarter of sites read above 6.7 gpg and the bottom quarter below 3.3 gpg.
Wells 4.6 gpg, rivers and lakes 5 gpg
1 groundwater samples from 1 wells put the median at 78.6 mg/L. 187 surface samples from 11 sites put it at 85.8 mg/L. In Grant County the rivers and lakes come out 0.4 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. 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 24,000-grain unit covers a week between regenerations. Expect about 105 lb of salt a year (3 bags of 40 lb, about $19), 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 $119 a year.
Sizing at 4.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 288 | 24,000 | 35 lb |
| 2 | 576 | 24,000 | 70 lb |
| 4 | 1,152 | 24,000 | 140 lb |
| 6 | 1,728 | 24,000 | 210 lb |
Grant County against the rest of Oregon
Among the 36 Oregon counties with data, Grant County is number 22 of 36 counting from the hardest. Across the whole country it is harder than 30% of counties.
Softest in Oregon: Columbia County at 1.4 gpg. Hardest: Malheur County at 17.8 gpg. Closest to Grant County: Klamath County (4.8), Union County (4.8), Baker County (4.6).