Water softener sizing calculator
Enter grains per gallon from your system’s Consumer Confidence Report, or pick a city below. A softener is optional below 7 gpg.
Typical hardness by city
| City | Hardness | |
|---|---|---|
| Boise City | 6.7 gpg | moderately hard |
| Garden City | 6.3 gpg | moderately hard |
| Kuna | 8 gpg | hard |
| Meridian | 6.6 gpg | moderately hard |
| Nampa | 7.1 gpg | hard |
Daily grains equal hardness (gpg) times people times 75 gallons, plus 3 gpg per 1 mg/L of clear water iron. The recommended unit is the smallest of 24,000, 32,000, 48,000 or 64,000 grains whose capacity at 70 percent covers a week. Why 70 percent. City values come from each system's CCR. If hardness is missing, the city page labels a regional default and does not guess.