Will a raccoon drown a small dog in swimming pool?

Yes, it is very possible. A raccoon can kill and eat a small dog very easily. There is a higher chance of the raccoon killing the dog if it is starving, and how aggressive the dog is. This is also very serious because if the raccoon has rabies and bights the dog intending to kill it, but doesn't, then the small dog will probably have to be put down or die anyway from diseases etc. So, basically, it's a good idea to keep your small dogs away from raccoons to be on the safe side.