RO water is fine to drink, although think twice before drinking DI water. Although I used to drink DI water a lot but many people have digestive problems from DI because it is too pure and their bodies aren't used to it. I've also heard that drinking DI can be bad because it can actually dehydrate you due to the fact that it lacks any minerals and it goes right through you. Soo, RO fine to drink, DI not so good.