Does anyone know of a receptacle cover (standard 120V GFCI duplex) that is suitable for a hosedown location. The ones I have seen are all called "weatherproof", & I'm not sure how well they will work in a wet location.
Try mounting the GFCI inside a Carlon NEMA 4X clear cover enclosure. Weatherproof covers are 3R, you need 4 or better. Or locate a GFCI inside the enclosure and install a standard waterproof receptacle wired to the load side of rthe GFCI on the surface. http://danielwoodhead.com/catalog/wiring_devices/WD_wrd.htm