How to Check Your Anode Rod

Water Heater Annual Maintenance

We’ve all heard the horror stories about water heaters becoming pressurized rockets that explode through the roof of the house or about families leaving on vacation and coming home to find the water heater has ruptured and filled the home with water. These are gripping tales of woe that seize the heart of every homeowner for many reasons. One, it’s because, while rare, the stories are true and two, it’s because water heater failures can cost thousands to tens of thousands of dollars in repairs and sometimes irreversible damage. 

signs water heater failing

Fortunately, there are many things you can do to prevent such catastrophes from happening. If you are regularly monitoring and maintaining your system, you can watch for trouble and hopefully prevent system failures.

We all know what happens if a car is scratched or damaged and water, road salt, and other corrosives are able to get at the steel frame: it starts to rust and break down. Your water heater, made of steel and lined with vitreous glass, could follow a similar path if damaged or unmaintained. Fortunately, your water heater is equipped with a part to help withstand corrosion. The anode rod, sometimes called the sacrificial anode rod, is crucial to the prevention of water heater failure. The anode rod is designed to attract the corrosive material in your water so that it will corrode before your water heater will. This is why it’s called sacrificial; its demise means your tank is spared. However, because the anode rod’s job is to corrode, it must be checked often to make sure it’s still protecting your tank. 

These instructions are designed to help the do-it-yourself homeowner take care of their own water heater. However, if you read the following instructions and feel like this might be a bigger job than you want to take on, call a plumber you trust to help.

Before performing ANY maintenance on your water heater, complete the following 4 steps FIRST to avoid the risk of water damage, scalding burns, electrocution, or explosion:

  1. Disconnect power at the breaker for an electric water heater.  
  2. Shut off the gas valve for a gas water heater and make sure the pilot light is extinguished.
  3. Close the cold water inlet valve or main water supply. 
  4. Turn on the hot water at a faucet somewhere in the house. No water will come out of the faucet; this simply helps to relieve the pressure inside the water heater tank.

First, you’ll need to attach a garden hose to the spigot at the bottom of the water heater. Make sure to direct the hose to a drain and be aware that the water coming out will be VERY hot. Open the spigot and drain a little water to relieve some pressure and heat inside the tank before opening the top for the anode rod.

Next, go to the top of your water heater and look for a hex head bolt. If you don’t see the hex head, it’s likely built into your water heater system. If the anode rod is built into the system, checking or replacing it will require the assistance of a licensed plumber. Keep in mind you also may need to pry open one of the plastic caps on the top of the tank with a flathead screwdriver to find it. Fit a 1 1/16-inch socket onto the rod's hex head on top of the heater (or under its top plate) and unscrew the rod. Pull the rod out of your water heater and remember to use caution because it’s probably very hot.

anode rod usage

Your anode rod should be around ¾ inch thick. If it's corroded down to less than ½ inch thick or coated with calcium, it needs to be replaced. 

If you can tell that the rod is corroded but can’t pull it all the way out due to low clearance above the water heater tank, you will need some cutters. Lift out a section of the anode rod, and, while holding it tightly, cut off the top. Continue lifting and cutting, lifting at cutting, until you get the whole rod out.

You can find replacement anode rods at your local hardware store and you can expect them to cost between $30-60. Once you have the new rod, wrap the threads with Teflon tape, put it back in the tank, and tighten it securely in place. If headroom above your tank is limited, you can purchase a segmented rod that will flex in order to get into the tank.

Note: Be sure to check the anode rod site for leaks 24 hours after replacement. If you detect leakage, you may need to tighten it down or use more Teflon tape to improve the seal.

It’s important to check this rod often to be sure that the inside of the tank isn’t getting corroded. Most manufacturers recommend checking the anode rod as part of your yearly water heater maintenance.

water heater maintenance - check anode valve

If at any time you feel overwhelmed, have questions or concerns, call a plumber you trust for help. If you don’t have a trusted, licensed plumber and are in the Utah market, call Any Hour Services and we’d be happy to send a plumber to your home to assess your system, perform any maintenance for you, and answer any questions you might have.


water heater maintenance - anode rod


Author: Amber Smith-Johnson
Copyright © 2019 by Any Hour Services


Jul 14th 2019

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