If you have water that smells, it can be because the annode rod inside the water heater has failed, the water in that section of piping has been sitting there for too long, or there is something wrong with your water source. If the annode rod has failed, you probably will need a professional, just because its difficult for you to pull out the old one and find a new one except through a wholesaler. If its that section of piping, just run it for a ten or fifteen minute period. If that doesn't help, there is something else wrong. If the water smells, because there is something in it, you can have your water tested by the water department in your area. Local governments provide testing if they supply the water. In addition, you can buy a test kit at the local warehouse hardware store.

good luck

Raymond VinZant Plumbing Prof.