From my personal experience, misting is not effective. If your goal is to keep up humidity levels, a humidifier would be a better option. On the other hand, if you feel the tap water in your area could be an issue, you might want to use distilled or rain water for better results.

A simple in-line water filter - something from a Hardware store - screwed onto a hose, should be good enough. You could filter a few gallons at a time, then you wouldn't have to get the filter out for each watering.

For humidity, one of the most efficient methods is to place the plant just above a drip-tray/saucer full of water. Place stones, corks, or other spacers in the saucer to keep the bottom of the pot above the water-level. I was able to bring a Dizygotheca elegantissima (False Aralia) back from the brink of death with this method.

Josh