Honey bee colonies use water for three main jobs: evaporative cooling of the hive on hot days, diluting crystallised or thick stored honey so it can be eaten, and feeding larvae, whose food is mostly water. On warm days a colony can need several hundred millilitres of water — dozens of forager trips carried one crop-load at a time.
A single water forager can make 50 or more trips a day in hot weather, and colonies often "learn" and fiercely defend a favourite water source — which is why beekeepers are advised to provide a dedicated, bee-friendly water dish well before neighbours' pools or birdbaths become the default choice.
A cutaway beehive next to a water dish, where forager bees fly back and forth carrying water that house bees spread on the comb and fan to evaporative-cool the hive.
Hive core temperature depends on the balance between ambient heat load and the cooling water foragers can deliver — which itself depends on forager numbers and flight distance to the water source.
Raise ambient temperature to increase heat load, then adjust forager count and source distance to see if cooling keeps pace. Add a second, closer water source to boost delivery rate and watch brood risk fall.
Bees prefer scented, slightly "dirty" water over clean tap water because the scent cues help foragers relocate the same source — one reason chlorinated pools and neighbours' ponds can become unwanted magnets.