I have an Animal Plastics CB70 rack with the closed sides and back (not the economy plastics version) and the humidity stays roughly where I want it without much extra effort. I have a 5 inch water dish and a reptile basics plastic hide in each level, when I clean and refill water dishes I do splash the water from my fingers onto the newspaper substrate, but its not very much water. You may still want to mist the enclosure during dry months or times when your snake is shedding, but then again all rooms are different and your rack may require more or less moisture than mine does. Be sure to closely monitor your heat and humidity when you set the animals up, and you'll easily be able to tell if adjustments need to be made.