Water Leak Testing Papers

SKU: 33813-Co

$3.95USD or lower Each

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Indigo® cobalt chloride moisture indicator strips have a variety of uses. They indicate the presence of water by changing color from blue to pink at 50% relative humidity or higher. Use them to detect moisture in tiny cracks & crevices from masonry to circuit boards to science lab experiments in plant transpiration & combustion.


See our blog about water leak detection for more information or watch our video Water Leak Problems?. Available also in larger 8x10" (200x250mm) sheets for use in showing splash patterns. Extra large sheets up to 20x24" (500x600mm) can be ordered but there is a 100 sheet minimum.

If that still doesn't work, try our 3 sheet sample pack of Water Contact Indicator papers. It comes with one 8x10" (200x250mm) sheet each of cobalt chloride, chlorophenol red & universal pH test papers.

Indigo® cobalt chloride test papers are backed by lab test documentation. See below for Certificate of Analysis, Stability & SDS.


  • Number of paper strips (100) per vial is approximate.
  • Minimum shelf life of 3 years; much longer if kept stoppered.
  • Changes color instantly in liquid H2O; reacts to 55% RH or higher.
  • Color reverts from pinkish-white to blue in warm, dry environments.

Test Strip Documentation

Stability Statement Certificate of Analysis SDS
Indigo Cobalt Chloride Test Papers Stability Statement Indigo Cobalt Chloride Test Papers Certificate of Analysis SDS Sheet
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