If you have a glass tank and open screen top, that's going to make things difficult. But what we do with ours is place the water bowl under the heat lamp - it helps with the humidity a ton. Keeping towels over the side that doesn't have the heat lamp is good. Remember it's always a little more humid and warm in his hide than the rest of the cage, but depending on how much water is in there..if it's just a little I wouldn't worry. If it's a puddle your humidity is too high. Do you have a humidity measure?