What Is a Water Heater Anode Rod?
A metal rod inside the tank that corrodes on purpose so the steel tank does not. When it is used up, the tank starts to rust.
A rod of magnesium or aluminum, often with a steel core, that hangs inside a tank water heater and is more reactive than the steel around it. Corrosion attacks the rod first, a process called sacrificial protection, so the tank wall lasts longer. Most rods last 3 to 5 years, less in soft or very hard water. A rod worn down to its core wire, or coated in white scale, has stopped protecting the tank.
Checking one takes a 1-1/16 inch socket and some leverage, since the hex head on top of the heater is often tight. Replacing a worn rod costs $20 to $50 and can add years to a tank's life. A flush done at the same time clears the sediment the rod sheds. Tanks with a soft-water supply and a smell of rotten eggs often need a different rod type.
Fixes that use this
Heating & Cooling
No Hot Water? Start With the Reset Button or the Pilot
Electric heaters have a hidden red reset button behind the access panel. Gas heaters have a pilot. Both explain most sudden losses of hot water.
Time20–60 min Cost$0–$45 moderate
Heating & Cooling
How to Flush a Water Heater in 1 Hour and Save Energy
Flush a tank water heater once a year to clear the sediment behind popping noises and slow heating. Shut off power, attach a hose, and drain the tank.
Time60–90 min Cost$0–$25 moderate