An anti-rat flap member for sewer/draining pipe check is removably attached tothe valvebody. The valve body defines an interior volume therein which is preferablysubstantiallyopen and unobstructed (except for the flap member). The flap member acts bothas a sealto prevent the back-flow of sewage/drainage water and is normally in a closedposition toprevent the passage of rats. The flap member comprises a row of sharpprojectionsattached by known means (such as integrally molded, glued, rivetted orscrewed) to theoutermost side of the flap member facing the downstream section of the valve.Theprojections must be at an angle to the surface of the sheet, preferably at anangle whichwill prevent the rodent from gnawing and biting or even lifting the flapmember withtheir mouth.
