Household Water Softener Sizing Guide

Recommended Water Softener Capacity

Measured Water Hardness gpg (grain per gallon)

 Household Size

 5 (gpg)

10 (gpg) 

 15 (gpg)

 20 (gpg)

 1

30,000

30,000

 30,000

30,000

 2

30,000

30,000

30,000

30,000

 3

30,000

30,000

30,000

 40,000

 4

30,000

30,000

 40,000

 40,000

 5

30,000

30,000

 40,000

 45,000

 6

30,000

 40,000

 45,000

 45,000


Sizing is based on the following:

  • Average daily usage of 80 gallons/person/day (please check your own water usage, water bill)
  • 80% softener capacity, allowing a margin for excessive water usage.
  • Regeneration occurring every 5 days


Note: Water hardness above needs to be increased by 5 for every 1 mg/L or ppm of iron (Fe) in your water.  Elevated iron levels are usually associated with well water usage.