How to Fix a Leaking Water Heater

Close-up of drain pipe leaking water
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A leaky water heater could be a major problem but an easy fix. The first step in repairing your water leak is to determine its origin and cause. Some of the reasons that your water heater may start to leak include:

  • Age
  • Bad plumbing either from the installation or age
  • Poor maintenance
  • Loose drain valve
  • Too much tank pressure

Why Water Heaters Leak

Water heaters that are not installed correctly can begin leaking prematurely. A loose drain valve will slowly begin to leak over time, but this problem is easy to remedy; simply tighten the valve when you notice the leak.

Over time, pressure to the tank can cause the most damage to your water heater. This can be caused by several issues, including high incoming pressure to the water heater and a bad pressure relief valve. These issues are better addressed by a licensed plumber, as they can be complicated and potentially dangerous to deal with.

Most water heaters last between 10 to 13 years, and if one is leaking from the bottom of the tank inside the burner compartment, old age might be the cause. This is caused by years of sediment building up in the bottom of the water heater tank. Eventually, the bottom of the tank will rust through and begin to leak. In this case, repairs are not really an option, and the water heater needs to be replaced. This can be done DIY; however, if you are not certain that you possess the skills needed, you can always call a plumber.

Fixing Your Water Heater Yourself

If you intend to do it yourself, these are the basic steps to do so:

  1. Shut off the water supply to the water heater, also shut off the electrical power, if you have an electric water heater, or the gas supply if you have a gas water heater.
  2. Drain the water out of the water heater tank by opening the valve at the bottom of the tank near the floor. It may be helpful to attach a garden hose to the drain valve and run it to a nearby drain to avoid a big mess.
  3. Once the tank is empty, you can disconnect the gas line, flue pipe and water lines for a gas water heater, or the power wires and water lines for an electric water heater. The water heater may still be a little heavy, so you may want to use a dolly to remove it from your home.
  4. When it is out of the way, clean up the area to make it ready for the new water heater. Once the area is prepared, you can set the new unit in place, and begin reconnection of the water lines, the gas or electric supply and the flue pipe for the gas water heater. Make certain in the case of a gas water heater that you check your gas line joints with soap bubbles for gas leaks.
  5. Turn the gas/power on, and begin refilling the water tank. For the gas water heater, you must also remember to light the pilot light. You also want to make sure that the thermostat is set to the temperature that you want, the most common setting is 120 degrees Fahrenheit. At this point, your new water heater should be set to go.

Replacing a Water Heater Valve

Water may also leak from the pressure relief valve on the water heater. This could be caused by either a faulty valve or a high-pressure situation in the water heater. If the valve itself is bad, it can be replaced in several steps:

  1. Shut off the water heater, shut off the water supply and drain some of the water from the tank.
  2. Lift the little lever on the valve to discharge any remaining pressure.
  3. Use a wrench to unscrew the valve from the tank and replace it with a new valve.
  4. Use teflon tape on the threads of the new valve before you screw it into the water heater.
  5. You should then be safe to refill and turn the water heater back on.

Most other leaks you may encounter are repaired by tightening loose valves or fittings on the water heater and the connected pipes.