When distilled water started to become hard to find, I opted to invest in this product to make my own for my Opal ice maker. It is easy to use, but given our hard water around here, it is a little hard to keep clean. The bottom gets pretty caked over with calcium (or whatever that is), and it's hard to remove, even with the provided cleaner. However, it doesn't seem to impact the performance at all, and we've made probably 5 batches a week for a few months now. If you need a continuous supply of distilled water for whatever reason, this definitely does the job.