Water Heater Anodes

What is an Anode and why is it important?

Why Do Water Heaters Corrode (Rust)?

Corrosion in water heaters is associated with the passage of minute electrical currents which travel through the metal and the water. Corrosion takes place at the anode which is where the current releases ions to dissolve in the water. Cathodic areas develop at the tank walls where the circuit is completed and provided there is an effective anode working inside the tank, no corrosion can, or will, take place. Once the original anode stops working, the steel tank will react with other incompatible metals such as the copper pipes, brass fittings and the element(s). Once this occurs, the tank wall becomes anodic and corrosion (rust) commences.

How Do Anodes Stop Corrosion?

Anodes are manufactured from a special grade of magnesium and they protect steel by a sacrificial electrochemical action. When a magnesium rod is fitted to a steel tank filled with fresh water, a current will constantly flow through the water between the rod and any exposed steel area on the tank wall. This protective current is produced by the magnesium releasing ions, and this results in the anode corroding instead of the steel tank.

Recommended anode replacement guide

What About Older Heaters?

The older a heater is, the greater the likelihood of it having little or no remaining active anode thus tank corrosion may have already started. While that corrosion cannot be reversed, it can certainly be arrested by the introduction of a new anode.

Difficult or Restricted Access?

NO PROBLEM! Chiswick Plumbing have Flexi-Link anodes. They allow us to replace anodes where there is insufficient space for a standard anode replacement.