We buy purified water for us humans to drink and sometimes I give my dog that. He particularly enjoys cold water so on a hot day I would sometimes pour some cold water into his bowl. On normal days, i just give him tap water. Tap water is relatively safe although I would recommend that people attach a filter on their faucets and boiling it for extra precaution. I haven't encountered any problems with giving my dog tap water. I mean, what is good enough for humans should be good enough for dogs right? Anyway, what I do is throw away old water before I pour in new water into his bowl or bottle just to make sure that it is clean. If we just keep on just refilling their bowls and bottles, there might be "germs" that have accumulated there that might make them sick.
