Masking tape, also known as Painters tape, is water-resistant rather than waterproof.
Masking tape has to be non-porous as it is used by painters and decorators to mark off areas where they do not want paint to go. If it was porous paint would soak through it and create a mess.
Despite this masking tape is not waterproof because it is paper based which is what makes it easy to tear.
This means that it doesn’t perform well for long when directly exposed to water.
For example, it is not suitable for patching a leak or for using outdoors in the rain as the water will cause the paper to break down and the glue to lose its adhesiveness.
Interested to find out how other types of tape fare against water? Also Read: