Water heaters are beautiful devices. They provide us with hot water for washing dishes, laundry, and showers. The latter is probably the best of the bunch. How many cold winter mornings have been saved by a hot shower? However, as we can tell from things like the Grand Canyon water is quite good at eroding and corroding substances with which it is in constant contact. So, why wouldn’t the interior of the water heater rot away over time? Why aren’t we replacing our water heaters every couple years before they spring a leak? The answer is in a magnesium or aluminum anode.
The Sacrificial Anode
The anode is a simple bar of magnesium or aluminum that hangs into the tank. It sacrifices itself and corrodes instead of the vital steel inside the tank. By doing this it vastly extends the life of your water heater. When the anode is shriveled and withered away it requires the simple matter of replacing the anode.
Why Doesn’t the Steel Corrode
The answer is rather scientific. Every type of metal from steel to iron to zinc, has a different level of reactivity of the galvanic scale. When two different metals are placed in water together the “nobler” or less reactive metal will corrode first. By doing so, the anode slows and stops the corrosion of the steel. So, next time you take a hot shower, have a moment of silence, a prayer, or just a shout-out to the anode that has made that hot water possible.