If you google it you'll see that bees like chlorinated water as the chemicals sort of draw them in. You're neighbors probably don't bother chlorinating their pool when it's not summer and warm.That's what I don't understand - why does my water become less attractive in the Summer?
This has been my experience. During the fall and winter I leave out a bucket of warm water (with an aquarium heater) to keep my bees out of my neighbors hot tub. During the summer when my pond is warm(ish) they will go there, but when the water gets cold they dont want to go to the pond anymore.My guess is that the swimming pools are warmer than other waters in spring and fall. Water temperature is important as flight muscles don't work so well when bee bodies are cold, and hauling cold water doesn't help that problem.
It can also depend a lot on the area. In dryer places it is not hard to get to a point where you are several miles from a natural water source that is available year round.How do wild bees survive without filled water bowls 50' away? I wouldn't sweet it with a pond that close.