What is a backwater valve?

A backwater valve, also referred to as a reverse flow valve or a sewer check valve, is a device installed in a building's plumbing or drainage system. Its primary function is to prevent water or sewage from backing up into a property during floods or heavy rainfall. When wastewater flows out of a building, it passes through the backwater valve, which only allows it to flow in one direction out of the property and prevents any reverse flow or backup.

The valve typically consists of a flap or gate that opens when water flows in its intended direction and then closes when there is backflow. It is usually installed in the basement or crawl space of a building in a vertical pipe between the sewer line and the foundation drain.

Backwater valves require regular inspections and maintenance to maintain their effectiveness, as they can become clogged or damaged over time. They can also be combined with other flood prevention methods, such as sump pumps and exterior drainage systems, for added protection.