Water is necessary to flush the toxins out of your shepherd's system, to aid in digestion, and to help maintain a static body temperature — for a start. Additionally, puppies and dogs can lose a substantial amount of water through panting, exercise, and a rise in the outside temperature.

If your German shepherd has access to clean, cool fresh water at all times, he will be able to maintain his appropriate water balance on his own by drinking when he needs to. If you withhold water from your shepherd, he can quickly become dehydrated. He might also get into the habit of gorging on water if he's been without it, drinking vast quantities of water at one time because he perceives it to be a limited resource.

If you provide your shepherd with a constant supply of fresh water and he suddenly begins drinking all the time or not at all, consult your veterinarian immediately. There are several conditions that can cause a drastic change in a dog's voluntary water intake, and none of them are diseases that you want to ignore.