One of the best investments I ever made was a water distiller. 99 bucks, if buying bottles of distilled it pays for itself in no time. Plus you know you are truly getting distilled water and as an added bonus no plastic. I store it in 1/2 gallon glass jugs (beer growlers).

I understand the reason why many health practitioners recommend distilled water, for it's one of the most "pure" forms of water available.
However, did you know distilled water is actually acidic? You can check the pH yourself, or research online, there are plenty of tests done on distilled water.

I am just posting this out of concern for those of you consuming ONLY distilled water. Basically when water is distilled (boiled, evaporated, condensed), it becomes acid and negatively charged, and since anything in a negative state must be balanced, it leaches minerals and toxins from the body.
Hence, short-term consumption during a cleanse would be beneficial. However, if you continue to consume distilled water for a long period of time, the body will lose all of it's precious minerals, and your body will become acidic and mineral deficient. There are many other long term health issues of consuming only distilled water.

Here you can find more details and real studies done on distilled water:
http://chetday.com/distilledwater.htm