The Oatey 4” PVC Backwater Valve is a sewage check valve designed to prevent pumped water from flowing back into the basin. The valve has an elastomeric seal inside the flapper that ensures a tight seal, preventing fluid from entering. The 4” PVC Backwater Valve can accommodate access sleeves made of Schedule 40 pipe, has hub-by-hub solvent- welded connection and can protect low areas or basements from backflow or waste from street sewers. The threaded access cap incorporates a neoprene seal for positive sealing and can be tightened or removed by hand. The valve fits DWV pipe, and can be adapted for sewer and drain pipes. It also comes in a 3” size and is offered in ABS or PVC material.