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Hard Water Calculator

Hard water makes detergent less effective. Find out if you need more, plus whether a water softener would help.

Water hardness

Not sure? Check your local water utility's annual report — or buy a $5 hardness test strip.

Detergent type

Your water

Moderately Hard

100 ppm

Recommended detergent dose

70 mL

That's +10 mL more than the standard 60 mL dose.

Slightly more detergent or a small dose of borax helps lift stains. A whole-house softener isn't necessary.