FusionGuy09 tells us how to fix a leaky toilet. You should be able to hear the leaking toilet. First thing you want to do is turn the water off. You can do this by reaching behind toilet and turning a lever. Next, flush the toilet to remove the water from the tank. Remove the flapper and check for wear with your finger (don't worry about the water back here, it's sanitary). Look out for cracks or pieces coming off. Also check the valve seat for spots without a seal. If you find parts that aren't working, take them to your hardware store for an exact fit.