As others have stated pass on any fountains or waterfalls. Chams just do not see that as a water source. Chams will need to see water droplets on leaves or dripping water. Misting, good plant cover and proper humidity keeps the hydration where it should be. I know these fountains look cool but to a Cham they see it as a toilet sometimes and unless you want to wash it out daily it's not worth it. If they for whatever reason start to look dehydrated after doing all the previously stated there are other means to rehydrate so don't panic and add one. One thing I do to help with hydration and make my Cham happy is offer a couple hornworms a week. He absolutely loves them like they are some kind of delicasy. Hornworms are basically a bag of fluid and since he loves them so much he will even walk right out of the cage on to my hand to get it.