So many people worry about the chlorine levels in tap water... I hate to tell most people, but probably 80% of the US water supply no longer uses Chlorine, but chloramine, which in all honesty doesnt not evaporate sitting out... letting water sit out does do a few other things to tap water so it is a good idea for every day watering but not necessary.
Chlorine also will not effect your plant in any way, it effects microbes in the soil, which is a coin toss up if it is truly going to effect your plant in the long run. You treat your plant right, water it when it needs and not over water it, give it the nutes it needs when it needs it will be a very happy plant and will make you very happy in the end!