water heater anode rod pic1Why is a water heater anode rod important to you? This is the quiet dutiful soldier of your hot water tank. Often called a 'sacrificial anode' it keeps your hot water tank from rusting. It is quiet in the sense that there is no obvious sign that it has gone bad.

If you need an anode rod there are a couple of concerns, first of all, what type to you want? See the articles,  'Types of Metal for Anode Rods' and 'Anode Rod Installation Types' to find out what the choices are and reasons why you have choices. Getting the old one out can be a problem, see the information below for what you need to do.

Of course you will need a new anode rod, the article 'Purchasing an Anode Rod' will explain where to look for one at.

These rods are usually made of aluminum or magnesium. The latter being the better of the two and more expensive. Explaining how and why an anode rod works is complicated and pretty dull. We will skip that discussion. Simply put, the anode rod is more reactive than the steel in your hot water tank. Therefore, it will corrode or 'sacrifice' itself in place of the steel in the tank.

When the anode rod disintegrates the water will start reacting with the steel and your tank will rust. The expected life of an anode rod is about five years. The hardness of the water and temperature will affect the life span. Softened water will cause an anode rod to wear out in as little as six months. See what you need to do to check and replace your anode rod by reading on.

Hot Water Heater Anode Rod - The Issues

What Can You Save? - Access to the hot water tank is a problem. The anode rods are long and get very brittle over time. This makes taking them out a little troublesome. The going rate for an anode replacement is $200 to $300. The part will cost between $25 and $40. Your savings could be as high as $260 if you do it yourself.

How Hard Could It Be? - Water heater anode rods are not the easiest thing to change. Plan on a little patience and effort. These repairs will have a Difficulty Level of: A Bit of Work. These repairs require a Skill Level of: Handyman. For and explanation of the terms in this section, see 'How to Use This Site'.

Check the Simple Things! - Sorry, nothing simple with this one. Just getting it out to inspect it involves some work.

What Can Go Wrong? - An aluminum hot water heater anode rod can swell and split. This may make hard or even impossible to get out without breaking it. It will rattle around in the bottom of the tank if it breaks. When you have low head room, you will have to bend them it. They can be quite brittle, again, breaking it is a problem.

Removing a Water Heater Anode Rod

Removing an anode rod can be a tough job if the water tank is old and the connection has corroded.

For an electric hot water heater the first thing you want to do is shut off the power. On a gas hot water heater turn off the gas. Close the cold water inlet at the top. Run some hot water and check the pipes if you are not sure. Open a hot water valve in a sink near the hot water tank to relieve any latent pressure.

Use a socket wrench or box end wrench to remove a hex head anode. It should be an 1 1/16" wrench. It is a good idea to spray some penetrating oil on the nut. Loosen the nut to remove the anode rod, it is attached to the nut. This could be tough, you may need a breaker bar.

For a full size hot water tank, the anode rod might be pretty long. Possibly forty inches or more. Do you have enough clearance to get it out? No, then you will have to bend it or cut it to get it out. This is the tricky part. Pull it up as far as you can. Put the vice grips on it at the top of the tank. You don't want it to break off and fall into the tank. Try bending it. Will it bend? Yes, then good bend it and pull out another section. Reset the vice grips and bend it again if you need to. Is this fun or what?

Is it too brittle? It might be better to cut it with a hack saw. Make sure you secure it with the vice grips. Remember, you don't want pieces falling into the tank. Cut it and pull more out and cut it again if you need to.

The combination anode will come out in a similar way. The difference is that you need to use the pipe wrenches to take it out. There should be a union above the tank. Loosen the union first. Always use two wrenches to take apart plumbing fittings. After the union is free you can loosen the nipple going into the top of the tank. You may have clearance issues, follow the instructions above for cutting and bending an anode.

Installing a Water Heater Anode Rod

The method for installing a water heater anode rod will vary slightly depending on the type you have. See the articles 'Purchasing a Water Heater Anode Rod' and 'Types of Water Heater Anode Rods' for information on getting the right one.

Installing a Straight Anode Rod

A standard straight anode rod will screw into the 3/4" opening where the old one came out. You can use some teflon tape or pipe dope on the threads. The metal will still make contact even if you use something on the threads.

The biggest challenge with a straight anode rod is having enough clearance to get it in. If your water heater is in the basement or a closet and you have a full height ceiling, you will probably be all right. A lowered ceiling of any kind may give you a problem. A standard anode rod is around 40", so you need that much clear area above the water heater.

Once you have started the anode rod into the threads, tighten it down with a socket wrench. Turn the water on and check for leaks.

Installing a Flexible Anode Rod

A flexible anode rod will have multiple spots that it can be bent at. Depending on the amount of clearance that you have, you will use one or more of the bends. You will want to straighten the flexible rod as you put it into the tank.

Remember you have to turn the nut back into place, you don't want the anode rod twisted like a pretzel inside of the tank. It does not need to be perfectly straight, but somewhat straight is best.

Use some pipe dope or teflon tape on the threads and tighten the rod into place.

Installing a Hot Water Inlet Anode Rod

This type of anode rod is installed at the hot water outlet pipe. The section of pipe between the outlet and the union in the line will need to be removed. If you are replacing the same type, you had to remove this section to get the old one out.

When converting your hot water tank to this style, you may have to modify the length of the pipe between the outlet and the union. Getting a flexible connection is the best approach.

The anode rod screws into the outlet for the hot water. Then you install the pipe between the outlet and the union. The last thing you would do is tighten the union. Use some pipe dope or teflon tape on the connections. For this connection you will need two pipe wrenches.


Starting Up the Water Heater

After the anode rod is in you have to close any valves you opened and turn the water back on. Check for leaks and that is it. This hot water heater anode rod project is history.

For and elecric water heater turn the breaker back on. A gas water heater will need the gas valve turned to on and the pilot light lit.


Wow, that was a little bit of work. I wish I could say that 'I hope it was easy', but I know it wasn't. This is a bigger plumbing repair. You can comfort yourself with the knowledge that you are prolonging the life of your hot water tank.

Replacing your hot water tank is an even bigger job. To be honest, hauling a old water heater away is a big job. Completely replacing your water heater, well, you will want to get some rest. Your hot water heater anode rod should be good for another five years.