Water contact indicator tape changes from white to red when water contacts the edges of this tape, and stays red even when it dries out. The tape will not change if exposed to high humidity environments, only from liquid water.

Water contact indicator tape is a great way for checking electronic devices or mechanical instruments that are not designed to operate in wet conditions. It is also good for finding water leaking sources.

There is a red dye (in dry form) on the back of the water indicator tape. It is separated from the front of the tape by a white wicking material. When water leaks in from the side of the tape it activates the dye which wicks through to the top side. Because the dye colors the wicking material, it stays red even when the tape dries out.

Courtesy: 3M

Water contact indicator tape is a great way for a manufacturer whose products may be exposed to water but warranty does not cover water damage to verify a customer’s claims. For example:

• Mobile phones, 2-way radios, cordless phones, personal communicators, and pagers
• PDAs, gaming consoles, MP3, and CD players
• Digital, film, and video cameras
• Lap top computers and keyboards
• Rechargeable batteries and chargers
• Vacuum cleaners

Other possible applications:

• Locate leaks in roofs, basements, or on pipes
• Flood or ocean's high tide indication
• Visual indication that you need to change a baby’s diaper
• Targets for squirt gun games
• Embedded in the tag of dry-clean only clothes
• "Don't walk in with wet feet" warning for possible electrocution

Common specifications for commercially available Water contact indicator tapes are listed below:

	Construction:	From top to bottom: Transparent PET top film (Polyester), Backing (Indicator layer), Adhesive (Acrylic), Release liner
	Color:	White, turns red permanently when wet
	Dimension:	12 inch x 180 yards
	Adhesion: (ASTM-D3330, 90° Peel Adhesion, 72 hr dwell)	Stainless Steel: 82 ozs/in (88 N/100 mm) Polycarbonate: 47 ozs/in (52 N/100 mm)
	Thickness: (ASTM D-3652)	Tape: 0.0090" (0.229 mm) Release Liner: 0.0020" (0.051 mm)
	Humidity Resistance:	55 °C, 95% R.H.

•	Pros:
	-	Clear, unmistakable indication of water contact
	-	Light weight, low impact on the total weight of applied products
•	Cons:
	-	Increase cost of applied products