Is it possible city water is bad for my iguana?

Our iguana is a healthy green color and normaly eats pretty well. We have been giving him alot of calcium, he gets it on his food, we bought calcium gravel for his cage and he gets a calcium spray once daily. We also have a heating pad under the aquarium to keep him warm, change his water every other day and bought a special UV light. The brown discoloration of his back legs and tail has changed to a healthy green and he uses his back legs much better but somethin is just not right with him. He seems I don't know like off balance or lethargic or something. Is that normal as he grows or could there be something in our city water that is bad for him? Maybe I should start buying bottled water and see if that helps. Any advice????