What happens if the installed height of a trap is too low?

When the installed height of a trap is too low, the primary concern is the potential for loss of trap seal. The trap is designed to hold a certain volume of water, creating a barrier that prevents sewer gases from entering the living space. If the trap is positioned too low, there is an increased risk that the water level in the trap can be siphoned away due to various factors, such as wastewater flow changes or negative pressure conditions within the drainage system. This can result in the trap seal being compromised, allowing harmful gases and odors from the sewer system to escape into the environment, ultimately posing health risks and violating building codes.

Maintaining the appropriate height for a trap is crucial for ensuring the trap seal is retained, thus preserving the intended function of the plumbing system. The other options may occur under different conditions, but the most directly related consequence of having a trap set too low is the loss of the trap seal.