What is the primary purpose of a backwater valve?

What is the primary purpose of a backwater valve?

• A. Allow backflow from sewer into building
• B. Block backflow into building
• C. Vent sewer gases
• D. Improve flow in sewer main

Answer: (B)

The main idea is protection against sewer backups. A backwater valve is a one-way device on the building’s sewer line that allows wastewater to flow out to the sewer, but automatically blocks flow trying to come back into the building when the municipal sewer backs up. This prevents sewage from rising into basements or lower floors during backups. It isn’t used to vent sewer gases (venting is done by a vent stack), nor does it improve flow in the sewer main. Proper installation on the building drain and routine maintenance are important so the valve can move freely when needed.

The main idea is protection against sewer backups. A backwater valve is a one-way device on the building’s sewer line that allows wastewater to flow out to the sewer, but automatically blocks flow trying to come back into the building when the municipal sewer backs up. This prevents sewage from rising into basements or lower floors during backups. It isn’t used to vent sewer gases (venting is done by a vent stack), nor does it improve flow in the sewer main. Proper installation on the building drain and routine maintenance are important so the valve can move freely when needed.