A photodetector is provided with a housing that has a discontinuity formed in an outer surface of its light transmissive portion. The discontinuity serves to inhibit liquid droplets from adhering to the outer surface of the endface in the region where the discontinuity is located. Alternative embodiments of the present invention include discontinuities formed in the outer surfaces of housing windows which have flat inner surfaces or inner surfaces which are shaped to formed lenses. By preventing liquid droplets from adhering to the outer surface of the window, the present invention prevents the reflective liquid surfaces of droplets from creating false signals for the photodetector by reflecting light back from the light source toward a light sensitive component.