I don't have an RO/DI unit yet. And will have to depend on alternate water sources for a while. Today I purchsed a bottle of Hinckley Springs purified water for top offs. The label says: Purified by reverse osmosis and/or distillation, filtered and ozonated to ensure quality. Contains purified water with selected minerals (potassium bicarbonate, calcium chloride, magnesium chloride)dded for taste. Mineral amounts are not nutritionally significant. It listed an 800 number, so I called and asked if copper was used anywhere in the process, he said no. I highly doubt if lead is used because the problems with it are so widely known. If someone here had a mind to we could start testing bottled waters and posting the results. What would we need to test for? In the past (10 years ago) I had used filter cartridges that you attach to the spigot, but the nitrates (from farm runoff) and phosphates are so high in this area they just burned the cartridges out after 20 gal or so. The cartridges cost about $25 each it wasn't cost effective. I also question if an RO/DI unit won't have the same down fall as the cartridges, that is they will burn out quickly.