To fix a leaky water heater, the owner should first determine where the leak is occurring. The five major points for leaks are the cold-water inlet, hot-water outlet, the pressure relief valve, the drain or the tank. All of these leaks, except those from the tank, are repairable.
Leaks around the inlet or outlet are usually due to a loose connection. Most require tightening the connection. Soldered connections that are leaking require soldering again using a plumbing torch.
A faulty pressure relief valve allows water to drip from the opening, even when the valve is closed. If the valve is loose, water sometimes leaks around the connecting threads. Replacing the faulty valve or tightening the loose one usually repairs the problem.
The drain valve, located at the bottom of the tank is another potential leak. If the owner has recently drained the tank, it sometimes leaks through the valve. Adding a brass hose cap to the threaded outlet end of the drain is usually sufficient to stop the drip.
The life expectancy of a water heater is about 15 years, but water conditions can reduce it greatly. Over time, the minerals in the water supply cause corrosion of the tank. Once the tank starts to leak, the owner should replace the water heater immediately. A water heater with a leaking tank is not repairable.