I also have a leaky faucet in my tub. But I know what the problem is, but I don't know how to fix it. When we had the leak it was only the hot water. So we turned off the water and took the hot water handle apart to find out that the rubber washer had been melted, so we replaced it and turned the hot water in the basement down. The water worked fine......until we took shower. We now have replaced the washer (same problem it's been melted) 11 times and turned the hot water down just as much. And we still can't seem to fix it. Like I said everything works fine until we take a shower. I should mention that when we bought the house a year ago a shower was not installed in the tub so we've attached a water massager to it and take our shower that way.