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Testing

How to Test Water Hardness at Home

The ways to test hardness at home, how accurate each is, and how to turn the result into a softener size.

By Softenry Editorial · Updated October 2026

The short answer

Strips give a band in seconds; a drop-count kit gives a number in gpg; a lab or multi-test kit adds iron and pH for wells.

Methods

Home tests
MethodResultUse
StripsBandQuick check
Drop-count kitNumber in gpgSizing
Lab or multi-test kitHardness plus iron, pHWells

Doing it

  • Run the cold tap a minute; test unsoftened water.
  • Follow the kit's timing exactly.
  • Record the result in gpg (divide mg/L by 17.1).

Kits we cover

On The Go 481108 Hardness Test Strips, Culligan 1035250 Hardness Test Kit, Droplytix DW-R20-S10 Digital Water Tester. Then size the softener.

Products mentioned

Hardness test strips · On The Go

On The Go 481108 Hardness Test Strips

Hardness test strips · 50 tests

On The Go
Drop test kit · Culligan

Culligan 1035250 Hardness Test Kit

Drop test kit

Culligan

Questions readers ask

How accurate are hardness test strips?
Good enough for a band; use a drop kit for a number to size with.
Where do I test before buying a softener?
An unsoftened cold tap, after running it briefly.