Field glossary

Backwater valve

A check on below-grade drainage that stops a surcharged storm main from backing water up into a low area

Used across 4 Anvilfield field guides, most in Plumbing.

Also defined as

One-way valve on the building drain or sewer that opens for outflow and closes against sewer backflow
A check valve in the drainage line that closes against a backup from the public sewer

Where this shows up