Sizing
Water softener capacity calculator
See how many grains of hardness your household removes between regenerations.
Your home
Start frompeople
gpg
gal/person/day
days
Capacity used31,500 grainsbetween regenerations
Per day4,500grains removed
Water300gallons a day
The math
- 4 × 75 gal = 300 gallons a day
- 300 × 15 gpg = 4,500 grains a day
- 4,500 × 7 days = 31,500 grains
The formula
grains between regenerations = people × gallons per person per day × grains per gallon × daysA softener's rated capacity changes with its salt setting, so compare this number to the capacity at the setting you plan to use. A water test and a look at your plumbing should settle the final choice.