FullCalculator

Water Softener Size Calculator

Water Softener Size

Formula

Capacity = (People × 75 gal/day) × Hardness (GPG) × Regeneration Days

Frequently Asked Questions

How do I determine the right water softener size?
Multiply daily water usage (people × 75 gallons) by water hardness (GPG) to get daily grain removal needed. Multiply by days between regeneration (usually 7). Choose a softener with at least that grain capacity. For example, 4 people with 15 GPG hardness need a 32,000-48,000 grain unit.

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