It seems most posters here are weekenders and carry jugs of water from home. As stated earlier, we are full-timers - our home is always with us - there's no way we'd be carrying water in jugs from 'home'.
For the past 16+ years we have filled our tank with water from many different sources. We use an excellent filter when filling the tank (not one of those WalMart cheapies). We also have an excellent filter at the kitchen sink. So ours is filtered twice. We have never sanitized our holding tank...filtered water goes into it and it's filtered again when we drink it.
If we bought all our water for the past 16 years, I can't imagine what it would have cost!!! As 'doxiemom11' stated, read the labels on your bottled water to see where it comes from...Better yet, drive to one of those fancy 'springs'.