Wie lange hält eine Opferanode ?

When does a sacrificial anode have to be replaced?

Normally a sacrificial anode in a storage tank lasts for at least 2 years. To ensure the best possible protection, we recommend checking the condition of the magnesium anode one year after buying a new storage tank and replacing it after two years at the latest. After that, the anode replacement can be adjusted depending on the condition of the protective anode. Furthermore, the maintenance demands of the manufacturer should be considered.

Which factors influence the durability?

The question of how long a sacrificial anode will last is asked daily by our customers, who reach us via our contact page. Various factors may influence the durability of the anode. In order to ensure the minimum protection period of 2 years, the magnesium anode must be dimensioned and installed in a proper way. The following causes affect the service life of a sacrificial anode:

  • Material: Cheap cast anodes or our extruded magnesium anodes (longer durability)
  • Condition of the enamel layer inside the storage tank: The more hair cracks there are in the enamel layer, the faster the protective anode will use up.
  • Temperature of the boiler. Check if the temperature is set higher than recommended by the manufacturer.
  • Water quality: Do you have very hard water?
  • Softening plant based on saline solution.

Operating a salt-based softening system will have positive effect on your water quality. However, the sacrificial anode will use up much faster than usual. An annual check of you sacrificial anode is strongly recommended. We know from experience that the magnesium anode can be completely used up after a year due to a softening system.

How can I tell how long a sacrificial anode lasts?

There are different opinions from different manufacturers. We have summarized the most important arguments:

  • Protective anode has to be replaced at the latest, if the diameter has reduced to 15-10mm.
  • Alternatively, it should be replaced if it's used up more than 2/3.
  • If you did an insulated installation: Measurement of the protective current: < 0,3 mA


In general we recommend a replacement of the sacrificial anode after 2 years. Most inquiries reach us from customers who have never exchanged the anode in 5-10 years. Unfortunately we have experienced a few cases where the storage tank was rusted through after 5 years already. If you are not sure about what sacrificial anode you need, you can contact us any time. We will be happy to help.