A good rule of thumb (or in my case, paw) for telling good water from bad is this:
If you found the water yourself and went into it voluntarily, it's good.
Good regardless of what your mommy may say! My mommy has no appreciation for water that has an interesting aroma or color, and she almost always tries to keep me out of it.
If your parents try to force the water on you, it's bad.
Daddy sometimes squirts me with a spray bottle for no reason at all when we're riding in the car. He usually does it when I'm standing with my feet on the front console urging Mommy to drive to the dog park faster. As soon as the slightest bark escapes my mouth, he squirts me and pushes me into the back seat. Then he brandishes the spray bottle menacingly if I bark even a little bit under my breath. Water in spray bottles is bad.
The very worst bad water is a bath. Baths are humiliating! Even though I'm pulling as hard as I can in the other direction, Mommy just picks me up and puts me in the tub. Then she makes me sit or even down while she pours water all over me, Furthermore, baths always involve shampoo, which smells unimaginably horrible. She rubs it all over me and then, to make my misery complete, pours water on me again. She says it's to get rid of fleas, but I think it just makes them mad. They're obviously just as anxious to get out of the water as I am because they keep jumping higher and higher on my body as she pushes me down.
Mommy gave me a bath last night. I won't forgive her for that until she has taken me to the dog park at least three times, and by then she'll probably want to give me another bath.