Anode rods and their effect on steel piping

In summary, the type of anode rod used and the frequency of water replacement can affect the corrosive effects on both galvanized steel and copper pipes in a water heater.f
  • #1
TL;DR Summary
Trace amounts of your water heater's anode rod (usually aluminum +zinc or magnesium) enter your pipes. Over time particles from the anode rod will enter your pipes and cause corrosion. I am trying to figure out which materials would create less corrosion to the pipes over the long term.
Water heaters have a sacrificial anode rod inside of them to protect the steel tank. These rods are usually made of magnesium or aluminum, and sometimes zinc.
Please note that zinc anodes are made of a combination of aluminum and zinc, 1 proportion of zinc to 10 proportions of aluminum.

I would like to know the corrosive effects of these anode rods on galvanized steel and copper pipes.
Galvanized pipes typically have a 50 year life span and rust from the inside until they are clogged with rust. You will also notice rust colored water at your faucet.
I am not familiar with something similar happening to copper piping.

Which of these materials would be more or less corrosive to these 2 types of pipes?

While on this topic, would a water heater with stagnant water not being used wear out its anode rod at the same pace (~3 years) as a water heater that's constantly being used and having the water inside it replaced with fresh water?

Thanks for your help!
 
  • #2
The anode rods used in water heaters can be corrosive to both galvanized steel and copper pipes. The corrosion rate of the anode rods will depend on the type of metal used in the rod and the pH level of the water. Generally, aluminum anodes are more corrosive than magnesium anodes. Zinc anodes are the least corrosive of the three. The corrosion rate of galvanized steel pipes can be accelerated by the presence of an anode rod. The corrosion process begins on the inside of the pipe, forming rust that clogs the pipe, reducing its lifespan. Copper pipes are usually more resistant to corrosion caused by anode rods, but can still experience corrosion over time. A water heater with stagnant water is likely to wear out its anode rod at a faster rate than one that is constantly being used and having the water replaced with fresh water. This is because the fresh water helps to dilute any contaminants that may be present and reduce the corrosive effects of the anode rod.
 

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