An expandable liquid barrier having an expandable layer attached to an adhesive layer is disclosed. The barrier provides constant containment without restricting access or creating a hazard in an area. The barrier is generally low profile like a length of tape until contacted by a liquid. Once in contact with a liquid the barrier expands and provides containment of the liquid. One means for expanding the barrier in the presence of liquid is to provide an expandable fill, such as super absorbent polymer, between the layers. Other means for releasing expanding the barrier include using a water-soluble adhesive to hold a resilient expanding layer and providing contracting section which increases the profile of the barrier. The barrier may be used in combination with a switch to enable reaction to the spill.