In most cases a leaking water heater indicates tank failure and will need to be replaced with a new unit. There are two locations on a hot water heater that can leak water and will not actually require the installation of a new tank.
The T&P or Temperature and Pressure Relief valve is a safety device that is required on all residential and commercial water heaters. This valve is designed to relieve the pressure that can result from thermal expansion in extreme cases. The T&P valve is designed to release when the water pressure inside of the tank exceeds 150 psi or 210 degrees.
In order to fix this problem you need to diagnose the possible cause for the leak. Usually when a leak from the tp valve occurs we install a thermal expansion tank and a new tp valve. In rare cases the tp valve can actually discharge without reason. These are cheap valves that usually need to be replaced once they start to leak.
The drain valve on a water heater can start to leak from thermal expansion inside the tank. If you have a leak from the drain valve you should check the water pressure to be sure it’s not over 80 psi. If the pressure is too high consider a PRV or a thermal expansion tank.
In order to stop the leak from the drain valve you can either purchase a 3/4″ brass cap or replace the drain valve itself. Replacing the drain valve will require draining down the water heater.
Common questions regarding a leaking water heater
Q: How long should a typical water heater last before it starts to leak?
A: The average lifespan of a water heater is 15-18 years, however it’s not uncommon for a water heater to last 20 years or longer.
Q: Will my water heater rupture and make a big mess?
A: It is very uncommon for a tank to completely fall apart and flood the surrounding area. Most all water heaters manufactured within the last 25 years have a glass lining which will help hold the tank together and prevent complete breakdown.
Q: How long do I have before my leaking water heater stops working?
A: In most cases a water heater can leak for several days or even weeks before it stops producing hot water.