We have about a dozen hives and several nuks on a large deck near the house. On the deckis one of those fountains with a small submerged pump that pushes water up through a ceramic ball, the water trickles down the sides of the ball onto stones and seashells which hide the plastic mesh through which the water flows down to the pump again - it's like a saucer sitting over a bowl about 15 inches across and 10 deep - meant most likely for inside ambiance but somehow started using it outside and the bees (and squirrels, and cat, and heavens knows what else) found it. My point in all this is that most of these small fountains would probably work fine while looking good, if that's a concern. It does require access to electricity and there have to be things for the bees to stand on. There's usually enough rain to top it off but because of the pump we do keep an eye on the water level. I think "onlygoodSHBisadeadone" back aways, has something there about the footprint of moisture over an evaporating thing.
On the other side of the bee deck is a stand of herbs in trays filled with pea gravel. I see a lot of watering going on there after a rain. The bees seem to like that situation, too. Far and away the most lovely sight of a watering honey bee is one on a fuzzy leaf of blue-green sage, sipping up a raindrop.
But the watering source that gets the most use here is an almost everpresent mud hole about 100 feet from this particular bee yard. As someone said earlier, go figure.
Flying by the seat of my pants.