OK I like this build, its cheap, simple, and works. I hate washing the dogs, holding them down, etc etc. One changes I would do to this build (roughly $10-15 in cost). Maybe add in misters instead of holes. I like the authors other builds too. but again, I think I would use misters for the kid wash.
http://www.instructables.com/id/PVC-Dog-Washer-Self-Standing/