As everyone else has stated, tap water is fine. But just an fyi for everyone out there, distilled water is acutally BAD for most animals (and us too to a certain extent) because it contains NO trace elements or minerals. Most wild-type animals in our care (such as snakes, birds, rodents, rabbits, etc) really need those trace minerals found in regular tap water. Filtered water is fine because no filter can remove all particles of trace elements and minerals from the water. And if you have really hard well water like I do, or city water with added flouride, a Britta or other filter is really great. But distilled water is to be avoided as drinking water for you and your pets.