No hot water, pilot won't stay lit, or strange noises.
Tell us what you need. A licensed local contractor will contact you, usually the same day.
Common repairs include thermocouples and gas valves on gas heaters, heating elements and thermostats on electric heaters, and relief valves. A plumber will tell you whether repair is worth it for the tank's age.
Repair prices depend on the part and the heater type. Ask whether the trip fee is credited to the repair.