One could always stop by a grocery store and have a couple of choices to fill their tank or have separate drinking water, inexpensively.
Inside they sell 2.5 gal containers that have a spigot. Drinking water has been filtered, spring water may be ‘natural’. (keep in mind what is typically found in 'natural' water...)
If you are into balancing the weight of your RV and know your weights per tire/axle, these can help...
Also many have a 'vending machine' outside that will dispense filtered water in to your container.
Just some thoughts for you to ponder...
