umm, no chloramine does NOT evaporate, so you can't leave water out for a day or to to evaporate it like you can with chlorine treated water. The question that I have (and everyone else it seems) is whether or not the presence of chloramine in our snakes drinking water will greatly affect their health. When I think about it, I drink the tap water, and my dog drinks the tap water, but I treat the water before I add it to my fishtank. As far as the snake is concerned I haven't a clue how bad it would be. Also, I can't use the same product that I use for my fishtank to treat my snakes water because it contains lots of other chemicals as well. I used to use a brita, and even though I always cleaned it out and changed the filters when I should, the bottom always felt slimy, like there was bacteria growing in there, and I figured there must be bacteria living in the filters when it got close to the time to change them... so which is worse, chemicals or bacteria?