On a good day I get mine right from the toilet. Adds a bit of texture to my espresso, but can clog the grouphead. Just Kidding!!! Potable water is either supplied by your own private well or by your closest town (city). Larger cities almost always pull water from reservoirs and treat it properly and some of the small towns even have large wells that they pull from to supply residents, but it must be treated first as well. Having clean water is essential. If you have a well you need to have the water tested to see if anything needs to be added or taken out of it. Even having town supplied water isn't that great. Sometimes they can't remove all problems, just clean enough to get by with. Most municipalities use large amounts of bleach and when it reaches your house it can still have 3-4 ppm of chlorine in it, which is too high to consume for long periods of time. Later!