No, two different processes are used in the purification of the two, but in most cases baring post filtering contamination they are both very pure water. If your going to purify your own water, which is probably the best way to go, go RO/DI. But if your going to purchase water, get distilled. DI is also a very pure water, just few people go that route because of the expence and short life of the cartrages. If your DI cartrages are changed properly you sould have a good quality water.