out of reptile carpet can i put a piece of that fake wood that is thin behind cabinets under waterbowl or is it not safe for snakes used newspaper but got too moist and was afraid it would grow molds or fungus?

The newspaper you were using shouldnt have gotten too moist. Either your humidity is way too high or your water bowl isnt heavy enough where the snake wont push it over. I guess as long as the wood is sanded and wont possibly impale the snake or give it slivers it should be okay.