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.

Both gas and electric hot water heaters can usually be purchased with five- and ten-year prorated warranties. This will give you a good sense of how long the tank should last, as many heaters aren't made to last much longer than the specified warranty.

Tip

Hot water heaters can leak during the warranty period—if your warranty is still active and your hot water heater is leaking, in most cases the manufacturer will provide a new heater for free, though they may not cover the cost of replacement. Check your warranty for specifics.

If your hot water heater is leaking from the bottom of the tank and it's nearing or past the end of its warranty, it may be because of old age. 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 by experienced DIYers, but if you are not certain that you possess the skills needed, you can (and should) always call a plumber.

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.

Fixing Your Water Heater Yourself by Replacing It

Warning

Working with gas lines can be incredibly dangerous, and replacing a hot water heater is best left to qualified and licensed professionals. If you are an experienced DIYer, you're comfortable working with gas and plumbing lines, and you're determined to replace the hot water heater yourself, proceed with extreme caution.

If you intend to do it yourself, these are the very basic steps to do so and do not cover the whole scope of the project. Do further research before beginning, adapting any guide as needed to suit your space and heater types, and call a professional if you have any concerns about your ability to complete this project.

  1. Shut off the water supply and electrical power or gas supply to the water heater, carefully following any instructions listed on the front of the tank.
  2. Drain the water out of the water heater tank.
  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.
  4. Remove the water heater and clean up the area to make it ready for the new water heater. Reconnect all necessary pipes and lines.
  5. Turn the gas/power on and begin refilling the water tank.