General Pipe Cleaners’ Flood-Guard helps protect property in flood-prone locations. Available in 2”, 3” and 4” floor drains, Flood-Guard operates like a check valve to seal off water backup caused by overloaded sewers. Water flows normally through the drain until the sewer begins to back up, the company explains. The Flood-Guard float then rises to seal off the drain opening until water recedes. Flood-Guard also is available in a standpipe model for handling extreme, extended pressure.