can't you refill those at a culligan machine or similar? I have 3 5 gallon water bottles that I just refill when I am brewing or it is time to refile the soda water keg.
I admit, I'm suspect of what comes out of those machines. I'm buying distilled water to blend with my tap water. I know I wouldn't buy it from my local store because I don't trust that it isn't just tap water run through a hose.
Are those machines distilled, mineral, RO (does that have any minerals?) or filtered tap?