Basically I bought a humidifier because of the dry weather and the instructions say that if the tap water is too hard I should use filtered water instead because of the minerals. Would the tap water in dorms rooms suffice?
I think water in Los Angeles is hard. It has nothing to do with being ‘clean’. It looks like you bought a humidifier without a mineral cartridge to take care of that problem I think this will cause your machine to break down sooner if you use tap water. More importantly, it may put mineral ‘white dust’ particles in the air that are not good to breathe. I don’t know much about that so maybe you should google.
http://www.consumerreports.org/cro/humidifiers/buying-guide.htm
If you want, I could log in and look up consumer reports recommended models.