The most important thing to remember about bees and water is that bees
prefer to take their water from a spongy material rather that from a
standing pool of water.  Take a pond for instance.  Bees will drink the
water from the spongy edges of the pond where the water meets the soil
rather than taking the water from the middle of the pond.  Keeping this
in mind it should be easy to lure the bees from ponds or pools by
providing a suitable spongy delivery system closer to the hive.  The
best watering hole for bees I have ever stumbled upon is watered potted
plants.  My bees line up at the drainage holes to suck the water from
the soil after I water my houseplants which I set outside in the warm
weather.  In fact, my neighbor's swimming pool is actually closer to the
hive than my houseplants, but I've never had a problem.  The bees fly
farther to the houseplants because they prefer the delivery mechanism.
 
Serendipitously discovered by Aaron Morris