It worked for Joey, but I don't know why. You use it as their drinking water. Regular water has minerals in it, and the minerals may affect some dogs. If you decide to try it, make sure you buy "distilled water, not just regular bottle water, and make sure the water is safe for drinking, as some distilled water is only safe for appliances such as steam irons. Here's a great link with more information on what can cause tearing.
Tear Staining: The Causes & Cures