I have used the same anode rod in my Suburban water heater for four years and it is in the same condition as the day I put it in. Why is it not being depleted.
My '97 trailer still has the original anode rod and is in great shape. Must be the mountain snow run-off water. In the spring and at the and of the summer there is a slimy transparent build up on the rod. Whatever it is , I do not know. Compare it to the looks of a jelly fish. I just clean it off and put the rod back in. Between Sept. and May that still happens although the tank is empty.
You have outstanding water. We have great well water here and I can go 3-4 years on the same anode rod, Was not that way filling up with water from town a year or two at most.