A "Trap Seal" is a water barrier found in plumbing systems, specifically in fixtures like sinks, toilets, and floor drains. It is created by a small amount of water that remains in the trap, preventing sewer gases from entering living spaces. This water seal is crucial for maintaining indoor air quality and preventing unpleasant odors. The trap seal can be affected by evaporation, especially in infrequently used fixtures. To maintain an effective trap seal, it is recommended to periodically run water in these fixtures. Regular maintenance ensures that the plumbing system functions properly and that sewer gases are kept at bay.