Water Heater Anode

Executive summary: Replace the anode on your water heater tank if you haven't already.

In October 2023 I installed a natural gas domestic hot water heater. In June 2026 I had the opportunity to explore some of its features that I normally wouldn't mess with*, specifically, the sacrificial anode. 

Sacrificial anodes ("anodes") are important because they protect a water heater from corrosion and extend the useful life of the water heater. They say you need to replace anodes every so often. Anodes are made of a metal that corrodes more actively than the tank. When anodes are attached to the tank, which they are by a metal thread that screws into the metal tank, they attract the corrosion process to themselves and away from the tank.

As an aside, if you are a boater, this is exactly like the zinc anodes you attach to your boat's rudder or other underwater component.

That rusty piece of wire was once an aluminum rod about 3/4" in diameter.

In the photo above, the thing I'm holding that looks like a rusty dipstick is all that is left of the sacrificial anode that came with my tank. It used to be a 3/4" diameter rod of aluminum. Egads — I'm a believer. I've never replaced these things. My dad never replaced these things. None of my friends replace these things.

Breaking the anode's fitting loose is insanely difficult. Why do they make it so difficult when this is a scheduled maintenance operation? I have no idea. An impact driver is what I'd recommend for removing it. I inspected and replaced the anode that came with my new water heater and by golly it's a 3/4" dia rod of aluminum. I doped the plug with some pipe sealant, reinstalled it, and tightened it by hand to "tight enough" rather than to the insane gorilla torque that the factory used.

I've put a reminder in my calendar for 30 Sep 2028 to install a new anode in my new water heater. The replacement part is less than $20.00 at Home Depot.

* Why was I messing with my water heater? I needed to replace the 2023 hot water heater because it was leaking. I believe the leak was caused by damage that was sustained during shipping which smashed the gas valve. The valve was replaced under warranty, but I suspect the fitting it threaded into was compromised and eventually failed (maybe a weld), hence the leak.