when deionized water was needed by my science classes, I used a vertical column ion exchange resin pack, that was designed for most of the common dissolved compounds.... the front end (+ charged/cation) metal ions were usually the target... the refil pack was pretty pricy, but lasted a year or so (I'd go through about 3 gallons per school year in my class, the Honors/IB classes a lot more, but have no idea on total production) If you had an idea of the possible source of contamination you could be selective in your resin pack choice

as Izzy commented, those of us in Florida typically store water, and the commercial bottles are the way to go... just get a hand operated pump from your route delivery guy.. I do still have a shallow well, and 5gal bucket filter for .1micron critters

I've been toying with the idea of converting an old fish cooker to a heavy duty rocket stove... 2 1/2" or larger pipe, short 6" fuel inlet (with divider shelf at diameter... wood/fuel on top/air underneath) and a 8" stack to draw... could use one of these fuel efficient stoves to run a small still

haven't given up on my solar desal plant, just looking for a kiddie pool