Signs That I Need to Change the Anode Rod

By Tricia Lobo; Updated April 24, 2017
Prevent corrosion and change the anode rod on your water heater.

The health of your anode rod is of critical importance to the longevity of your hot water heater. The job of the anode rod is to be consumed, in order to protect the lining of your water heater from damage. Be vigilant for signs that your anode rod needs replacement, and be sensitive to conditions that could reduce the life of your anode rod.


If you completely soften your water, your anode rod it will corrode faster. Corrosion results not only from salt in the water, but from water softeners themselves, and may result in a bad water odor. Completely softening, over a period of six months or less, can cause an anode rod to corrode. Thus, if you soften your water, consider replacing your sacrificial anode with an electrical anode, which will not corrode in response to softeners.

Warning Signs on Anode Rod

To determine definitively if you need to replace your anode rod, remove it from the tank and examine it. Your anode rod should show signs of use, and look slightly "chewed up"; however, if you can see 6 inches of the steel core wire underneath, replace the rod. If the rod consists solely of steel core wire, as a result of corrosion, you should definitely replace it, although the tank's life might soon be over.

Passivated Rod

Some rods are nonfunctional. If, a few weeks into use, you notice that your rod looks untouched, it probably is not doing its job, and is not corroding to save your tank. You may wish to replace it, either with another rod of the same kind or with a nonsacrificial, electrical anode rod.

Aluminum Rods

Pay special attention to aluminum anode rods, which are particularly likely to require replacement. Aluminum rods are more likely than other kinds of rods to split off into little pieces, or to produce waste as a by-product of corrosion. Be vigilant for little pieces of anode rod in your water heater, or for a foam by-product that floats at the top of the water in your heater and shows up in your filters. All of these signs tend to indicate that your anode rod needs replacement.

About the Author

Tricia Lobo has been writing since 2006. Her biomedical engineering research, "Biocompatible and pH sensitive PLGA encapsulated MnO nanocrystals for molecular and cellular MRI," was accepted in 2010 for publication in the journal "Nanoletters." Lobo earned her Bachelor of Science in biomedical engineering, with distinction, from Yale in 2010.