Home Water Softener Sizing Calculator
Enter your water hardness level, number of people in your household, and daily water usage per person to find the recommended softener grain capacity.
About this calculator
Determine the right water softener grain capacity for your household based on water hardness, household size, and daily water usage.
Frequently Asked Questions
How is water hardness measured?
Water hardness is typically measured in grains per gallon (GPG) or parts per million (PPM), where 1 GPG equals about 17.1 PPM. You can get this from a water test kit or your local water utility report.
Why is there a 20% buffer added to the capacity?
The buffer accounts for variations in daily usage and ensures the softener doesn't have to regenerate too frequently, which extends resin life and improves efficiency.
How often should a water softener regenerate?
Most residential softeners regenerate every 3-7 days depending on household size, water hardness, and usage, though demand-initiated regeneration systems can vary this automatically.