the deer already know where the watering holes are. i dont think adding a small amount of water will "bring deer in"...maybe get them to stay a lil bit longer cause they can wash the bait down with a drink w/o having to come back and forth, but not bring in or hold deer.
we use buckets in the hog traps, buried of course, so we dont have to check em daily in summer, but that water gets nasty perty dang quick. if ya live in cold climate, yer bucket will freeze over when ya need it most, hunting season.