Reduce Flooding from Drains
Ken Hellevang, Extension Engineer
Use commercially available drain plugs if possible. Some hardware stores sell plugs that have a rubber center that expands to fill the pipe when the top and bottom metal plates are squeezed. Other options to plug drains are listed below.
If the grid over a basement floor drain can be removed, use a rubber ball to plug the drain. A flexible ball about 1 1/4 times the inside diameter of the pipe can be wedged into the drain to create a tight seal. The pressure might be quite high if water or sewage tries to come up so brace the ball securely with a 2X4 against the ceiling. Hold a board or piece of plywood on the ceiling and slide the 2X4 against the bottom of the board to avoid damage to plaster ceilings. For a suspended tile ceiling, remove a ceiling tile or two to get access to the ceiling joists. Span a piece of 2X4 across the two joists and wedge the vertical 2X4 between it and the ball.
If the grid over the floor drain is permanent, a partially inflated inner tube can be placed around the drain. Place a square or two of plywood (not particle board) on top of the inner tube. The plywood must be larger across than the inner tube to cover it. Brace this in place just as with the ball on the drain. Be prepared for some seepage.
Reduce flooding from other drains. Unbolt toilets from the floor and plug the outlet pipe using the same procedure as for floor drains. Shower drains can be plugged this way, too. Most washing machines and basement sinks have their drain connections about 3 feet above the floor so may not overflow if the water doesn't get that high. If necessary, these drains can be disconnected and capped or plugged with braced rubber balls.