Save Money on Water Heater Repairs and Replacement

Take thirty minutes to check and replace one inexpensive part inside your water heater and you can lengthen the heater's life and postpone several hundred dollars in repair or replacement costs. That part is the little-known "sacrificial anode". Yes, the anode sacrifices itself so your water heater's tank doesn't rust as quickly.

Replacing sacrificial anodes won't make a water heater last forever, but if you replace them as soon as necessary, you can double or triple the life of the water heater for under $50. It's a regular part of my money-saving lifestyle.

How sacrificial anodes work:

When two different metals are connected by a conductor, they set up an electrical field which will oxidize one of them and reduce the other. The metal that oxidizes corrodes (rusts), weakens and disappears. The steel of the water heater tank and the copper of the house's plumbing or faucets, when connected by water, makes an electrical field that will oxidize the steel. That means it rusts and eventually the tank leaks or ruptures.

To slow the destruction of your water heater tank, the manufacturers insert a "sacrificial anode". It's nothing more than a rod of a metal that will oxidize more easily than the steel. It sacrifices itself and protects the steel tank. When the rod runs out of the sacrificial metal, your water heater's tank is next to go. Replacing the sacrificial anode renews the protection and cost far less than replacing the tank.

However, you have to replace the anode before it is completely sacrificed and the tank starts to rust. Factors that shorten the expected five year life of an anode are soft water, high water use, and sometimes the incoming water chemistry. An annual check will be often enough to monitor the condition of the anode.

How to check the sacrificial anode:

1 - Find the bolt that holds the anode in place and make sure you have a socket wrench that fits the bolt
2 - Shut off the gas or electricity to the heater
3 - Shut off the water supply to the heater
4 - Open a hot water faucet in the house to release the pressure.
5 - Unscrew the anode and lift it several inches out of the tank. You may have to use WD-40 or other pipe lubricants and a long-handled wrench. Anodes are not easy to remove.

If you see a corroded tube about as thick as your index finger, the anode doesn't need replacing. Make a note on the water heater of when you checked the anode, and make a date with yourself to check it same time next year.

If you see some bare wire, or a skinny corroded tube, as shown in the picture, it's time to replace the anode. Reassemble the water heater and order the replacement. If the anode is swollen and cannot be removed, it needs replacement, but it's not a job for a homeowner. Start saving your pennies for the plumber.

IMPORTANT: The anode is a long rigid metal rod. If you do not have at least 4 feet of clearance above your water heater you will have to drain and tip the heater to replace the anode. As an alternative, order what is called a "flexible anode". It is segmented and can be bent between the segments to insert it.

How to replace the sacrificial anode:

Follow steps 1 through 5 above, but continue lifting until the anode is removed. Lower the replacement carefully into the tank and tighten the bolt. Make a note on the water heater of when you replaced the anode. Continue to check it every year.

Types of Sacrificial Anodes:

Aluminum: Aluminum anodes prevent corrosion, but the anodes expand as they corrode, sometimes expanding to be larger than the opening they were inserted through. This makes checking and replacing them difficult. Also, the debris from the anode drops into the bottom of the tank and requires more frequent draining to prevent sediment from clogging the hot water system.

Magnesium: Unlike aluminum, magnesium sacrificial anodes don't drop debris into the tank and don't expand when they corrode. However, they release hydrogen gas as they corrode. Under some circumstances, when the water contains sulphur, magnesium anodes can become colonized by bacteria that produce hydrogen sulfide with it's characteristic "rotten egg" odor.