A check valve is for use in a fluid system. A valve body has an inlet end, a valve cavity, and an outlet end. A valve enables a valve assembly to control the flow of fluid therethrough. A plug of the valve assembly includes tapered and non-tapered sections, the tapered section having a cross section that increases in diameter in a direction that is downstream from the inlet end of the valve body. A sealing ring is mounted to reciprocate on the non-tapered section and an elastomeric actuation ring is mounted along the tapered section. The tapered section biases the actuation ring to a normal position, at which the actuation ring contacts and positions the sealing ring in contact with the valve body and the valve assembly to prevent fluid from flowing out the outlet end of the valve body.