How It Works
The check valve includes a small floating ball or cone in the valve opening. Flows of water from the top of the valve push the float down and away from the seal and allow the water to flow down the drain.
Flows of water from below the valve push the float up against the seal and prevent the flow of water up through the valve and into the basement.
Installing the Check Valve
Install the check valve with the top at floor level of the basement. The check valve does restrict the amount of water flowing through the valve so a check valve larger than the original drain size may be appropriate.
The valve installs above a trap in the drain line. The best time to install a check valve is during the initial construction of the home when basement plumbing is installed.
Add a little water down the drain every week to keep the trap full. A check valve only stops liquids, not sewer gas, from backing up into the home.
Make sure the float ball or cone moves freely within the valve. Remove any debris that would interfere with the movement of the float.
Homeowners use check valves in basement floor drains or sump pumps only. The valve does not prevent sewage backups that reach the level of basement toilet bowls or other lower level fixtures.
Use other forms of drain plugs in basement fixtures if sewage backup is a concern.