They don't really like real cold water, probably because it chills them and makes it difficult to fly. Placing the container in a sunny spot will allow them to easily find it and will also keep it warm. This, unfortunately, raises another problem, mosquitoes. Mosquitoes will find this standing water an excellent place to breed if it stands for more than a few days. It is thus important to have a regular schedule to dump and refill the water container.
Lets protect our right to keep bees by avoiding problems.