Our Flood-Gate® Backwater Valve completely seals itself during emergency storm conditions or when the building is shut down. Built for long service life, the valve's body is constructed of corrosion resistant Duco coated cast iron housing, a stainless steel gate, and PVC diaphragm. Engineered for drainage control in all commercial. institutional, residential and industrial installations, this valve closes and resets completely automatically without any manual intervention or need for electronic controllers.