Temperature and pressure relief valve leaks, which are fairly common, can be fixed by ensuring the operating temperature is not too high and cleaning mineral deposits. The process of repairing a leaking water heater varies depending on where the leak occurs.
If a temperature and pressure relief valve continues leaking after ensuring the temperature and pressure is low and mineral buildup has been removed, a component within it might need to be replaced. Replacing the whole unit can fix these problems, but it may be best to hire an expert since improper installation combined with overheating can cause the water heater to fail catastrophically.
Drain valves sometimes corrode over time; fixing a leaking drain valve often requires replacing the nozzle of the unit or the entire unit. Often, the system needs to be drained entirely, and filling the unit only partially after replacing components can save homeowners time if the valve needs to be adjusted further.
Leaks on the body of the hot water heater may spell doom for the unit. Small cracks grow over time, and even patched cracks or holes are likely to keep growing as the unit heats and cools. Furthermore, these problems are sometimes caused by rust within the unit, and extensive rusting may render the entire unit inoperable and potentially unsafe.