What happens if the trap seal is lost?

When the trap seal is lost, foul odors can escape from the drainage system into the living space. The trap seal is the water that remains in the curved section of a trap, which serves as a barrier preventing sewer gases and unpleasant smells from entering a building. When this water evaporates or is siphoned out, the barrier is removed, leading to the potential for harmful and odorous gases to escape from the drainage system.

The scenario does not directly lead to overflow, no effect on water flow, or sewage backups, as those outcomes are typically related to blockages or system failures rather than the loss of trap seal itself. Therefore, the loss of the trap seal primarily impacts air quality, making the release of foul odors the primary concern.