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Understand Your Hot Water Heater: The Anode Rod and Rust

Water Heater
Water and steel are not usually a good combination due to the chemical reaction that causes rust. You might wonder how your steel water heater holds water for years without succumbing to corrosion. This is possible due to a sacrificial anode rod placed inside the tank.
Here's what the anode rod in your water heater does and why replacing it when needed prolongs the life of your tank.
The Purpose of an Anode Rod
An anode rod is made of aluminum, a mix of aluminum and zinc, or magnesium. These materials corrode more readily than steel. This rod is usually inserted through the top of the heater and suspended in the water. Its purpose is to corrode gradually and in doing so it prevents the corrosion of the steel tank.
This principle is known as galvanic corrosion, and it occurs when two metals are present in water and one affects how fast the other metal corrodes. Galvanic corrosion is a good thing in a water heater because it prolongs the life of a steel tank at the expense of a rod that is easy to replace.
Signs an Anode Rod Is Bad
Once the rod becomes ineffective, your steel water tank is in danger of corrosion. Inspect the rod every few years to make sure it is still in one piece and not eaten away.
The rod is supposed to have pits and holes as these are signs the galvanic corrosion is taking place as expected. If the rod appears to be excessively corroded or if part of it is missing, then the rod should be replaced.
Inspecting the rod is the sure way to know if it's bad, but there might be other clues. If you hear pinging coming from inside the heater, it might be due to a broken part of the rod bouncing around inside the tank. Rust in the water is another sign that could indicate the rod is no longer working and the tank is starting to corrode.
Your water heater may not have any signs of problems, but if your heater is several years old, or if you have a water softener that can corrode the rod faster, you should take a look at the rod just to confirm it's in good shape.
A Bad Rod Can Be Replaced
If you're concerned about the condition of the anode rod due to the age of your water heater or due to problems you're having with sediment, unusual noises, or odors, then call for a plumber to inspect the rod.
A rod has to be replaced before it becomes useless. If you wait too long and the tank starts to corrode, it may be too late to save the tank. If the rod is still working, but near the end of its life, the plumber can replace it with a new rod.
While other parts of the tank might give you problems due to age, those parts can often be repaired to keep your water heater going. When the tank rusts, repairs may not be possible, making it necessary to have a new tank installed.
A plumber can help you choose the right anode rod based on the quality of your water, the temperature of your tank, and how often the hot water is used. Changing the rod may involve emptying the tank and flushing it to clear out debris and slime that's accumulated from the old rod.
If the anode rod in your hot water heater needs to be changed or just inspected, call First Class Water Heaters and we'll help you maintain this vital component of your hot water tank.