I haven't tested it, but I doubt very much that rain water would be even close to pure enough. When I lived in UK you would see sand on your car after the rain which apparently came from the Sahara. Now when I look at city air and you can see smog, I can't help wondering how much of that gets knocked out of the sky with rain water. I've seen references claiming rainwater being around 20ppm, but suspect it could be way higher than this in some areas. Maybe if you're very fortunate with your geographical location it could be better.
Paul B >To: silver-list@eskimo.com >Date: Sunday, September 13, 2009, 12:38 PM > > > Rely on my advice, or rain water? > >For those in hard water countries, >you could distill the rain water. > >Smitty