It needs pure water, so Rain Water should work (unless you're in a bad environment), Distilled Water would work too. Boiled will NOT work, from what I understand.

Distilled water is usually available from local stores and is pretty cheap. I use a turkey baster to water my plants, a baster-full or two a day is usually enough to keep a plant happy and doesn't mess up the soil too much.

Using tap water is bad for the CP because of the natural mineral and salt contents, not to mention fluoride or chloride added to the water. All that will kill your CP and boiling water doesnÂt solve the issue. Not only that, as some water evaporates through boiling, all that is left concentrate in the water. Avoid tap water!

Best choice of water is always distilled water because the chemicals and salts above are not present, 2nd choice is reverses osmosis, and rainwater is 3rd but you have to be careful. Rainwater may sometimes pick up impurities in the air.