I noticed my drinking dirty water last May. They seem to love the minerals from the dark composted soil in my raised garden beds. They’ve been at it again for the past few days.
April 2019 Postscript: Many urban beekeeping areas have policies in place to ensure that beekeepers provide a nearby water source for their bees. Part of the reason for this is to reduce the likelihood of bees crowding around neighbourhood pools to get a drink. Judging from my experience and online conversations I’ve had with reputable beekeepers and researchers, it seems that honey bees love stinky water, including highly chlorinated water in swimming pools. I’ve used marbles in a water dish to provide water for my bees (with okay results). I’ve used a bucket full of water and peat moss (which sounds great but didn’t do much). I’ve use clay, or terracotta, plant pot saucers filled with water and rocks and bits of branches (which, for me, works better than the other two). But a leaky garden hose, especially if the water has chlorine, seems to work best. The hose can leak over rocks or concrete or organic soil, just about anything. Whatever produces the most stink and warmth seems to attract the most bees. Although I haven’t tried it yet, boardman or entrance feeders filled with water might be the easiest way to water the bees.