Messy-Man!!

Does anyone know how to get a soon to be three year old to leave the bathroom faucets alone? I swear, once he learned how to wash his hands and brush his teeth I've walked into a flooded bathroom daily. I've even decided to put chain locks at the top of the door. Low enough that the older kids can get themselves in, but too high for his little hands to reach! Sadly, I'm sure if I do that, he'll use his "Spidey-senses" and find a way to climb the wall to unlock the door! Any ideas??