A corrosion resistant check valve having plastic components in the fluid path is provided. The check valve broadly comprises an inlet housing, an outlet housing, a valve poppet, and a spring. The inlet housing has an inlet passageway and the outlet housing has an outlet passageway. The inlet housing and outlet housing are connected to define an internal chamber of the check valve. An inner portion of the inlet housing has a transverse wall which includes a valve seat surface and a central hole which defines a flow passageway between the inlet passageway and the internal chamber. The valve poppet is disposed within the internal chamber and has a disk-shaped body and a stem extending perpendicularly outward from a centerpoint of the body. The stem of the valve poppet is positioned in a central bore in a planar end surface of the spring. The planar end surface of the spring also includes fluid flow passages disposed about the central bore. In operation, the spring biases the valve poppet into sealing engagement with the valve seat surface to control fluid flow from the inlet passageway into the internal chamber. When the fluid pressure in the inlet passageway exceeds the biasing force of the spring, the valve poppet unseats from the valve seat surface and fluid flows around the valve poppet, through the fluid flow passages in the spring and out of the outlet passageway.