Anode Rod Replacement
Updated February 20, 2026
Inside every tank water heater, there's a metal rod designed to corrode so the tank doesn't. That's the anode rod -- a steel core wrapped in magnesium, aluminum, or zinc. It attracts the corrosive elements in your water and sacrifices itself over 3-5 years. Once it's gone, your tank starts rusting from the inside. A $25 replacement rod can add 5+ years to your heater's life.
Overview
Inside every tank water heater, there's a metal rod designed to corrode so the tank doesn't. That's the anode rod -- a steel core wrapped in magnesium, aluminum, or zinc. It attracts the corrosive elements in your water and sacrifices itself over 3-5 years. Once it's gone, your tank starts rusting from the inside. A $25 replacement rod can add 5+ years to your heater's life.
What to Know
Tools & Materials
- 1-1/16 inch socket and breaker bar (or impact wrench)
- Pipe tape
- Replacement anode rod (match length and type)
- Bucket and rags for drips
Step by Step
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Turn off the heater and relieve pressure
Gas: set to PILOT. Electric: flip the breaker. Close the cold water inlet. Open a hot faucet briefly to relieve tank pressure.
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Locate the anode rod
The anode rod threads into the top of the tank -- usually a separate hex head fitting. On some models, it's integrated into the hot water outlet. Check your manual if unsure.
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Remove the old rod
Use a 1-1/16 inch socket with a breaker bar. Have someone hold the tank steady. An impact wrench makes this much easier. Once loose, pull the rod straight up.
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Inspect and compare
A healthy rod is mostly intact with some surface pitting. A spent rod is thin (less than 1/2 inch), coated in calcium, or just the wire core. If more than 50% gone, replace it.
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Install the new rod
Wrap the threads with pipe tape. Insert and hand-tighten, then snug down with the socket. Don't overtighten. For tight ceiling clearance, use a flexible segmented anode rod.
Pro Tips
- Flexible anode rods exist for tanks in tight spaces -- they're segmented so you can feed them in without 4 feet of clearance.
- If hot water smells like rotten eggs, switch from magnesium to aluminum-zinc.
- Mark the installation date on the rod's hex head with a paint pen.
- A powered anode rod ($80-$150) pays for itself if you're replacing sacrificial rods every 2 years.
Mistakes to Avoid
- Never checking the anode rod at all -- most homeowners don't know it exists until the tank leaks.
- Using the wrong socket size and rounding off the hex head.
- Installing a rod that's too long for the space.
- Ignoring a rotten egg smell -- it won't fix itself.
When to Call a Pro
If the anode rod is completely seized, a plumber can remove it without damaging the tank. If the rod comes out and you see rust flakes, the corrosion has already started -- get a professional opinion on remaining tank life.
Bottom Line
A $25 anode rod every 3-5 years is the single best thing you can do to extend your water heater's life. Check it every couple of years, replace when spent, and you'll get the full 12-15 year lifespan.