What type of plumbing fixture must be separated by a water-seal trap?

Every plumbing fixture that discharges wastewater must be separated by a water-seal trap to prevent sewer gases from entering the living space. A water-seal trap retains a small amount of water, creating a barrier that stops odors and gases present in the drainage system from escaping into the home.

This principle applies to sinks, toilets, and bathtubs, as each of these fixtures discharges wastewater and is connected to the plumbing drainage system. By using traps, any potential backflow of harmful substances is mitigated, ensuring the safety and health of the occupants. This requirement is a crucial aspect of plumbing codes to maintain sanitary conditions within residential and commercial properties.