In general, wouldn't reverse osmosis water be safe for soapmaking? I understand the dangers of tap water, but now I'm curious about RO specifically.She does say that she uses "filtered" tap water. Than can be anything from a store-bought water container with a filter on it, to a water softening system, to a reverse-osmosis system... or a combination thereof. So it's possible that her water is filtered enough to avoid DOS. Again, I find this irresponsible, but I guess that's on her.