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Water Heater Troubleshooting Guide | How to Tell if the Anode Rod Is Bad in Your Water Heater

Anode rods are an essential component of tank-style water heaters. Most anode rods are sacrificial, meaning they are designed to corrode (instead of your water heater lining). Because they are meant to break down, they wear out every few years and need to be replaced. Tankless water heaters don’t have anode rods, but all standard tank-style water heaters do.

Read on to learn how to troubleshoot anode rod issues and replace bad anode rods, if needed.

If you need help now with a water heater issue, call your local Mr. Rooter® Plumbing at (855) 591-0128 for courteous, prompt service.

Types of Anode Rods

There are four primary types of anode rods found in both gas and electric tank-style water heaters, including:

  • Magnesium
    Magnesium is the most common type of anode rod. They corrode quickly, so they should not be used in homes with hard water.
  • Aluminum
    Aluminum anode rods are inexpensive, long-lasting, and flexible. These are perfect for homes with hard water.
  • Zinc/Aluminum
    Zinc anode rods are 10% zinc mixed with aluminum. If your water has a sulfuric smell, switching to a zinc anode rod should get rid of the odor-causing bacteria.
  • Electrical (non-sacrificial)
    These anode rods use electrical pulses to get rid of corrosive elements in your water. They do not degrade like normal anode rods; therefore, they are the longest-lasting option available.

Generally, anode rods are interchangeable, meaning that you should be able to replace your aluminum anode rod with a zinc one. However, always check your owner’s manual for guidance from the manufacturer. But before you replace your anode rod, you need to know how to tell if it’s going bad.

How to Tell If Your Anode Rod Is Bad

Smelly or discolored hot water is the biggest sign that something is wrong with your anode rod. When your anode rod has completely corroded, it can no longer protect your hot water heater lining. Your anode rod will go bad every five years or so.

If you suspect a bad anode rod is the cause of your water problem, here’s how to check if the anode rod in your hot water heater is bad:

  1. Close the water supply shut-off valve.
  2. Turn on the hot water on a sink or tub faucet for approximately a minute to relieve pressure in the hot water tank.
  3. Turn off the electricity or gas supply to your water heater.
  4. Attach a hose to the drain valve near the bottom of the tank. Place the end of the hose in a sink, tub, or bucket, and drain out several gallons of hot water.
  5. Check for rust or sediment in the drained water. If the water is discolored, gritty, or smelly, consider fully draining and flushing the tank.
  6. Locate a six-sided screw head on top of the water tank; this is the hex head. Unscrew the hex head with an impact wrench most of the way; unscrew it the rest of the way by hand. If the hex head is set below the top of the heater, you’ll need a 1-1/16-inch socket to reach it. Otherwise, you can use any kind of wrench.
  7. When the hex head is removed, you can access the anode rod. Use a spray lubricant like WD-40 to detach the anode rod from the water heater if it’s stuck due to corrosion. Remove it from the tank and check its condition. A corroded anode rod may look pitted; in serious cases, sections of the rod may be missing altogether.
  8. If the anode rod is corroded, it’s time for a replacement.

If the water did not seem rusty and the anode rod seems in good condition, reverse the steps above to restore your water heater back to normal and call a professional licensed plumber, like your local Mr. Rooter, to determine and correct your water problem.

Water Heater Anode Rod Replacement

If you determine that your anode rod is bad, it’s time for a replacement. To replace your anode rod, perform the above steps in reverse – using your new anode rod, of course! Selecting your new anode rod should be based on your water’s condition and your budget. For example, to get rid of bacteria causing your water to smell foul, go with a zinc/aluminum or electric anode rod. For the most economical choice, magnesium is the way to go – but be ready to replace it again in a few short years.

All types of anode rods (except electric) are available in flexible models. In this case, “flexible” is a bit of a misnomer. They don’t bend, but they do have short segments that snap together much like tent poles. Choose a flexible anode rod if you have less than 44 inches of clearance above your heater. This will make it easier to remove, inspect, and replace the rod in the future.

Mr. Rooter Can Resolve Your Water Heater-Related Troubles

Having a functional water heater is necessary to being comfortable in your home. Call on Mr. Rooter’s dedicated team of water heater experts for anode rod replacement and all other water heater troubleshooting and repairs. If you want the job done professionally, call us today at (855) 591-0128 or request an estimate online.