r/o water, is purified, but with a much stonger and finer filter than brita nd pur have to offer, basically almost squeezed to get out your impurities, insteda of trickled over carbon
you can get r/o buy purchasing, some lfs's sell it, and if you read the labels, you may find soem on the shelves at the grocier, the best hting in my opinion is to buy an ro unit, you can get one for between 100 and 150 online if you shop around, but you may have to look to find those prices
r/o water is probably about as good as distelled water, but distillers are a bit more money and much more costly to run
HTH