Water Heater (Answer)

Hey Darnell,

It sounds like you have a bad sacrificial anode in the water heater. The sacrificial anode is a metal rod usually magnesium or aluminum. This rod is screwed into the top of the water heater, and its job is to help prevent corrosion of the metal tank. This rod sacrifices it self, to be eaten away from electrolysis instead of the metal of the tank. Once the anode is gone the tank itself begins to corrode. Replacing the anode when needed will prolong the life of the tank.
With the noise and the weird greenish substance you described, I believe you have an aluminum anode rod. If your water has a high pH level, it will cause the aluminum anode rod to corrode slow and produce aluminum hydroxide (weird greenish substance). The aluminum hydroxide falls to the bottom of the heater, trapping heat, and this is what makes your water heater sound like a “coffee percolator”.

The best way to find out if your anode is aluminum is to look at the exposed anode rod nut located on the top of the water heater. If the top of the nut is smooth, that indicates the anode is aluminum. If the top of the nut has a large bump on it, it is a magnesium anode.

If you find out that the anode is aluminum, and the water heater is in good condition except for the noise and the weird greenish substance. You may consider having the water heater flushed out and replacing the aluminum anode rod with a magnesium anode rod.

Thanks for your question.

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