Only two things to add.
First, as resident fish geek, I need to point out that chloramines do not dissipate if you let the water sit out and "age." Most city treatment plants use chloramines specifically for this reason- no need to use air tight water storage if they don't dissipate. So you have to use a dechloraminator (most, if not all, water conditioners remove both chlorine and chloramines) in order to make the water "safe" for fish and amphibians. My snake gets the same treated water the frogs get. I use NovAqua by Aquarium Pharmaceuticals.
Second, when I was using the schools distilled water for my tree frogs, I had insane problems with bloating- the frogs would blow up to the size of a ping pong ball, with legs. That was when I realized that because the distilled water has NO minerals or salts or dissolved solids in it, and the frogs body DOES, anytime they contacted the water, way more water than usual would cross through their semi-permeable skin to balance out the percentages. This is a standard osmosis/diffusion concept, and I, the idiot biology teacher, totally missed it at first.
Shouldn't be as bad for snakes since their skin isn't permeable like a frogs, but I would still use caution.