Let’s talk about how to replace the sacrificial anode rod in a hot water heater.
First, this is a medium-difficulty DIY project, and you should exercise caution while working around hot water and also gas/electrical service.
You’ll find a video below so you can see what is involved. This will help you decide if you want to tackle this, or to call a professional plumber to do this for you.
Second, refer to the list of tools and supplies we have listed out below the video. Make sure you have these on hand before you start. It will make for an easier hot water heater anode replacement project, and minimize extra trips to the hardware store.
Third, I list a common snafu regarding ceiling height. You will want to solve for this beforehand. (I have a picture of this limitation at my house.) This will dictate the type of anode rod you buy for your replacement.
Fourth, you can read through each of the steps to change your anode rod which will provide more detail along with some helpful tips. Ready to get started? Let’s go.
Here’s How to Change Your Water Heater Anode Rod (Watch Video)
Watch the helpful video below to get an overview of the entire project from start to finish.
This will provide you with a visual aid for all of the steps required. This video was done with a Rheem water heater, but it’s the same general process for all water heater models.
Tools for water heater anode rod replacement:
Replacement anode rod (check your make and model)
A socket wrench (1 1/16 socket size) for hex rods
22-26″ bar or pipe (for leverage if needed)
Flat head screwdriver
Plumber’s tape (Teflon tape)
Garden hose
Are all water heater anode rods universal and the same size?
Yes, the thread size on both gas and electric residential water heaters for the anode rod is the same size in diameter. This is ¾”, and will be universal in 99% of the cases. However, not all anode rods are the same length.
If you have a smaller or short tank, often the case with 30-40 gallon units, you will need a shorter anode rod. The best plan is to simply look up your unit by name or model number. This will point you to the exact length and recommended type of anode rod for your unit whether it’s a Rheem, A.O.Smith, Bradford-White, Whirlpool, Ruud, etc.
Tip: Before you order your replacement anode rod, measure how much room you have from the top of your water heater to your ceiling. Is there enough “headroom” to easily replace your anode rod?
If not, or you’re unsure,choose a flexible anode rod. This flexible anode will come in a chained “section” rod that accommodates tighter spaces.
Here is an example at my house. Since my water heater sits on a raised stand in the garage due to local plumbing code, there is no longer adequate room to replace the anode rod with a standard length.
The ceiling is too low above this unit due to the water heater being raised off the ground, as required for a garage installation where I live. I will need to use a flexible rod when I replace my anode rod in the water heater.
See my limited clearance below.
Steps to change the water heater anode rod:
Here are the steps on how to replace your anode rod in a detailed format.
1. Turn Off the Water Supply: Before you start tinkering with the water heater, make sure you’ve turned off the water supply at the shutoff valve. Do this at the cold water inlet line to the water heater.
2. Relieve Pressure on the System: It’s a good idea to open a hot water faucet somewhere in the house to relieve any extra pressure within the tank.
3. Turn Off Power to the Water Heater: Next, turn off the electricity at the circuit breaker box when changing the anode rod in an electric water heater. Confirm this was the right circuit. For gas water heaters, turn the gas control valve to the off position. This will be successful if the pilot light goes out.
4. Drain Water from Tank: Attach the garden hose to the water heater drain valve. If your water heater is located in the garage, you can take the end of the hose outside to the yard. If your water heater unit is located inside the house, run a hose to a laundry sink or nearest drain inside the home.
Double-check your connections before you start. If using a drain in the attic, first test the drain with a small amount of water first before emptying several gallons. You don’t want to discover a drain pipe leaking inside the wall the hard way.
Now, drain some water from the water heater tank with a hose. The drain valve is at the bottom of the water heater, and likely opens by turning the flathead screw. Drain about 2-3 gallons of water from the tank, then close the valve. You want to remove some water while at the same time leaving weight in the tank for stabilization purposes.
Caution: Please be careful while draining as this water can be extremely hot. Also, you don’t want to drain too much because you want the weight of the water to hold the unit in place when you take the rod out. Keeping the heater tank still will avoid twisting and destruction of the pipe connections.
How to remove the old anode rod from a water heater
5. Locate the Anode Rod: To change the anode rod look to the top of your water heater unit. There is often a small plastic cap that covers the hex bolt. If you can’t see the bolt, it’s common to find a small amount of insulation that might need to be removed. You can clear this with a screwdriver.
6. Remove the Anode Rod: Take the 1 1/16 socket wrench and unscrew the anode rod. You will need to turn it counter-clockwise. Some anode rods don’t have the hex head, but instead are the nipple type. In this case, you will need an adjustable wrench. You will see some water begin to emerge, so you may wish to have a towel nearby.
Note: If you see excessive water, re-tighten the anode rod. Confirm the water supply is indeed turned off. Drain some additional water from the tank. Now, remove the anode rod by lifting it out of the tank.
Tip: How to remove stuck anode rod from water heater
If you can’t budge the hex bolt on the anode rod, grab that extra pipe from the tool list. You might need to apply extra leverage to get it moving.
Will I be able to recognize a bad anode rod?
This is where you’ll probably see a crusty and barnacle-like appearance, not unlike what you’d see on the bottom of a ship. This is due to corrosion. If the anode rod looks like this, you’ve made the right choice in taking a look to inspect it.
Don’t worry, this corrosion is natural and your sacrificial rod has performed as expected! This one below is really bad, but gives you an idea.
If your anode rod is too long to remove from your water heater due to space, you can use a hacksaw to cut it down to an acceptable size. Just make sure you keep a hand on the piece you are cutting, lest you drop it inside the tank forever.
How to replace the anode rod in hot water heater
7. Install the New Anode Rod: Now it’s time to replace the anode rod in the storage tank on the water heater. Locate the new water heater anode rod, and prepare the hex fitting with plumber’s tape. This Teflon tape will help with the seal.
You should always wrap plumber’s tape in the direction you plan to screw it so it doesn’t unravel. In this case, clockwise. Give it 5-7 wraps, and screw it back into place.
Turn the nut on the top of the rod slowly with your hand first, let the threads catch nicely. When the threads grab, you can then put some force to it. It won’t be nearly as hard to tighten as it was to loosen. Make it secure.
Prepare to Finish: Here is a quick checklist as you wrap up your project.
Pre-checklist:
Confirm you have fully tightened the hex on the anode rod.
Confirm your hot water faucet turned on or “open” in the house.
Confirm your drain valve is in the closed position.
Ready? Ok, let’s test it.
8. Testing: Turn the cold water supply back on
Now you can turn on water and fill your water heater tank back up. Head inside, and turn off the hot water you left open in the house. (The faucet will usually spit some air out with the water until the air is expelled. The tank should be rid of any air when the water runs freely.)
9. Check for leaks
Return to where you replaced the anode rod at the top of the water heater. Do you see any leaks or water seeping out? If so, wipe it away and see if it continues. If it does, you may need to turn off the water supply and re-tighten your hex. Don’t forget the plumber’s tape.
Work on this step until you have a tight fit with your replacement anode and there is no more leakage. It’s a great idea to come back over the next 2 days to again check for any leaks.
10. Finish up!
Now you can turn your power back onto your water heater, either at the circuit breaker box or the gas supply. Of course, you’ll need to re-light your pilot light if you change the anode rod on a gas hot water heater and cut the gas.
Final Thoughts on Changing the Anode Rod in Your Water Heater
Below are some common and related questions you might have about this same topic.
FAQ’s: How to Change the Water Heater’s Anode Rod
What type of anode rod should I buy to replace the old one?
You can easily search for the best fit by make and model. But in general, you can choose from these replacement options: Aluminum, magnesium, or zinc. You may wish to buy a flexible anode rod, or even a powered anode rod depending on your situation.
How often should you change the anode rod in a water heater?
You should change your sacrificial anode rod about every 3 to 5 years. The frequency will depend upon your hard water, usage, and if you have a water softener or well. You should inspect your anode rod every 3 years, and smelly water is one indicator that it might be due for a change. It will help prolong the life of your tank and can help if your hot water has become cloudy white.
How much does it cost to replace a water heater anode rod?
The cost to replace a sacrificial anode depends on the type. A standard magnesium or aluminum anode rod starts around $15-$20, with zinc alloys running $44. Flexible anode rods run $30-$40, with powered anode rods averaging over $100. Labor is free if you do it yourself.
Should you remove the anode rod in water heater?
You should remove your sacrificial anode rod in order to replace it during water heater maintenance, but not permanently. Some advice suggests permanent removal as a solution for smelly water but this is not advised. Removing an anode without replacing it will often void the water heater manufacturer’s warranty on the steel tank should corrosion occur.
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We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.
