The "duckbill" concept check valve has been in use for over 100 years in waterworks and commonly accepted for use in industrial process piping systems and in waste and storm water or sewer piping systems. The simple, one-piece "duckbill" sleeve eliminates moving components and intrusive body structures that create problems with conventional check valve designs. There are no mechanical parts that can freeze, corrode, bind, or otherwise inhibit smooth operation. Unlike conventional check and flap gate valves, the Vatac Duckbill Check valve does not require regular maintenance to replace worn seats, hinge pins, balls, or flappers.