Symptoms
- Rotten-egg smell in hot water suggesting an anode rod reaction
- Tank is several years old and anode rod has likely never been checked
- No visible leak, but you want to extend tank life
- Considering the anode as part of routine maintenance
Likely causes
- CommonAnode rod heavily corroded and nearing full consumptionOnce the rod is mostly gone, the tank itself starts corroding faster.
- CommonRod material reacting with sulfur bacteria to cause odorMagnesium rods are more prone to this reaction than aluminum or zinc-alloy rods.
- PossibleAnode rod never replaced since original installationMany homeowners are unaware this maintenance item exists at all.
What to do
- Turn off power (electric) or set gas to pilot, then shut off the cold water supply and relieve pressure by opening a hot water tap.
- Locate the anode rod access point, usually a hex head on top of the tank, sometimes under a plastic cap.
- Use a socket wrench, and often a breaker bar for leverage, to loosen and remove the rod for inspection.
- If the rod is worn down to the core wire or heavily coated in calcium, replace it with a new one of the same or a different alloy if odor has been an issue.
- Apply thread sealant tape to the new rod's threads and reinstall it, tightening firmly.
- Restore water supply, check for leaks at the fitting, then restore power or gas.
Tools and parts
- Socket wrench and breaker bar
- Thread sealant tape
Water heater anode rodSearch: “water heater anode rod replacement”
When to call a pro
If the rod won't budge with reasonable force, or there's limited clearance above the tank to remove it, a plumber has the tools and experience to extract it safely.
Safety
Use caution
Relieve tank pressure by opening a hot water tap before removing the anode rod, and be cautious of the leverage needed, since these rods can be seized tight.