You may not realize it, but bees need water too. They will seek out water sources close to their hive. They use water to cool the hive on hot days, to dilute honey and to help with digestion and metabolizing their food. Luckily, I have a pond with a waterfall in my front yard that the bees congregate to during the day.
Here is a video of them flying all around the pond while the waterfall is turned off.