What is the maximum distance above the fixture that a trap can be placed?

The maximum distance above the fixture that a trap can be placed is 10 inches. This is based on plumbing codes that aim to ensure that traps function correctly by allowing for effective drainage and preventing sewer gas from entering the living space. When a trap is positioned too high above the fixture, it can lead to a condition known as "trap seal loss." This occurs due to insufficient water flow, which may result in the trap failing to maintain the necessary water seal. This water seal serves as a barrier against sewer gases, which can pose health risks. Therefore, the established limit of 10 inches ensures that traps remain effective and compliant with plumbing standards.