Journeyman Plumber ExamPlumbing Code and RegulationsEasy
A plumber is inspecting a newly installed backwater valve on a building drainage system. According to the Uniform Plumbing Code (UPC), what is the primary purpose of a backwater valve?
- ATo prevent foul odors from entering the building.
- BTo allow sewage to flow in one direction only, preventing backflow from the public sewer.
- CTo relieve excessive pressure in the drainage system.
- DTo provide access for clearing blockages in the building sewer.
Show answer & explanationAnswer & explanation
Correct answer: B. To allow sewage to flow in one direction only, preventing backflow from the public sewer.
The primary purpose of a backwater valve is to prevent sewage or wastewater from flowing back into a building's drainage system from the public sewer or a flooded area. It's a one-way valve designed to protect the property from contamination and damage during surcharge events.
Why the other options are wrong
- A. Preventing odors is the function of a trap, not a backwater valve.
- C. Relieving pressure is typically handled by vents, not backwater valves.
- D. Providing access for clearing blockages is the function of a cleanout, not a backwater valve.
Backwater Valve Purpose
A device installed in a drainage system to prevent the reversal of flow of sewage or waste water into a building.
- One-way flow device.
- Protects against sewer backup.
- Required in flood-prone areas or where backflow is possible.
Memory trick: Backwater valve, a one-way gate, keeps sewer floods from sealing your fate.