An anti-rat flap member for sewer/draining pipe check is removably attached to the valve body. The valve body defines an interior volume therein which is preferably substantially open and unobstructed (except for the flap member). The flap member acts both as a seal to prevent the back-flow of sewage/drainage water and is normally in a closed position to prevent the passage of rats. The flap member comprises a row of sharp projections attached by known means (such as integrally molded, glued, rivetted or screwed) to the outermost side of the flap member facing the downstream section of the valve. The projections must be at an angle to the surface of the sheet, preferably at an angle which will prevent the rodent from gnawing and biting or even lifting the flap member with their mouth.
