The Drain Flood Protector works like a check valve to seal off water back-up caused by overloaded sewers.  Water will flow normally through the drain until the sewer begins to back up. Then the Drain Flood Protector float rises to seal off the drain opening until the water recedes.  It only takes a screwdriver and a couple of minutes to install a Drain Flood Protector.  Once in place, it can prevent property damage and a very messy clean-up job. Gaskets are made of molded rubber, and all metal parts are plated or stainless steel.