Dogs tend to have sensitive tummies, so it’s most important to prevent your dog from drinking contaminated water. This caution applies to standing water and running water, as well as tap water. Both running water and standing water outdoors can be contaminated by wildlife and atmospheric contaminants, and tap water may have chemical contaminants that affect your dog more seriously than they affect you. Your dog should have access to fresh filtered water at home, and bottled water that you bring along away from home.

A dog can easily be taught to drink from a squirt bottle. My Doberman learned quickly to avoid water she finds outdoors in favour of drinking from a bottle, even if it isn't a squirt bottle. Snow is a more difficult matter, however, because dogs love eating snow, and it may become contaminated in the same ways that water does.

My 75-pound Dobe runs hard when we go out, and in an hour or so drinks about a litre of water to prevent dehydration in the warm weather; in the winter she needs about half a litre.

Of course, be sure to clean bottles and bowls regularly, especially in the warm weather, and be careful to avoid vinyl containers. Stainless steel bowls can be cleaned more thoroughly than plastic ones.