If your bathtub faucet is leaking hot water, it's likely due to a mineral buildup in the pipes. When water is heated, minerals like calcium and magnesium can become deposited on the inner walls of the pipes. Over time, these deposits can build up and cause the pipes to become constricted, which can lead to a leak. There are a few things you can do to clean the mineral deposits out of your pipes and prevent them from coming back. You can start by running a solution of vinegar and water through the pipes. This will help to loosen the deposits and flush them out of the system. If the vinegar and water solution doesn't seem to be doing the trick, you can try using a commercial pipe cleaning solution. These solutions are designed to remove mineral deposits and other buildup from pipes. Once you've cleaned the pipes, it's important to take steps to prevent the problem from happening again. One of the best ways to do this is to install a water softener. Water softeners work by exchanging the minerals in the water for sodium ions. This helps to reduce the amount of mineral buildup in the pipes. If you have a serious problem with mineral buildup, you may need to replace the pipes. This is a more drastic measure, but it may be necessary if the problem is severe. If you're not sure what's causing your bathtub faucet to leak hot water, it's a good idea to call a plumber. They'll be able to diagnose the problem and recommend the best course of action.