Alright, my first post here. Honestly I probably won't post much since i'm just the do it yourself kind of guy and I don't mess with any plumbing issues that often. And please bear with me since i'm not the most knowledgeable with items like these.

Anyway, in my garage I have a 91 gallon A.O.Smith gas water heater. The thing has been in use for 15.5 years. It's been drained and refilled a couple of times but that's really it. Due to a foul sewer like smell when anyone turns a shower on I've recently learned that water heaters tend to have an Anode rod in them to help prevent corrosion to the interior of the water heater itself, and I also learned that these rods are supposed to be replaced around every 4 or 5 years. My research has basically told me the smell is because the Anode rod in the tank is in need of replacement.

The confusing part is I looked on the top of my water heater and I found a plug. I removed the plug and began to dig into the foam insulation to find the top of the Anode rod, all in following how-to videos i've seen on YouTube. Funny thing is from the videos i've watched the plug for the Anode rod is closer to the center of the tank and not the edge where this plug is. Also after I removed the plug and was digging into the insulation I kept going deeper and deeper into it while finding nothing so it seems the plug was probably the original fill for the foam insulation. THERE ARE NO OTHER PLUGS ON THE TOP OF THE HEATER. I cannot find where the Anode rod is if there is one at all. I am absolutely certain there is no other plug on the top of the water heater, I have triple checked.

Is it possible this water heater doesn't have an Anode rod? Or maybe this brand is just a piss poor design where the Anode rod isn't serviceable? I'm totally open to suggestions on what to do about the smell in the showers. The only bright side is that after letting the shower go for a few minutes the smell thankfully does go away, but it's always back the next time someone takes a shower.

some water heaters have a nipple type anode rod. it is on the hot side.
call the manufacturer to make sure before you remove the hot side nipple.

After 15.5 years, the only thing left of the anode rod would be the metal wire core, if that even survived this long.

Sounds like(91 Gallon) a Big-o-Stone lined tank to me....no anode rod.

Oh joy So it's either no Anode rod or that F*ed up one that goes in the hot side of the heater. After more than 15 years I guess I can finally justify having the old water heater ripped out and a new tankless one put in its place.

It is time to replace it but I would not go with Tankless. Too expensive, technical and requires too much draining and cleaning with vinegar and water mix.

I don't know about too expensive to buy a tankless ???

here is a big box 91 gallon gas heater with a 3 year guarantee..

almost 5 thousand dollars..

[www.homedepot.com]

Tankless water heaters Do not save money.They are nice for Gym's and large familys with alot of teenagers but no one has ever shown me the savings because they can't.Any savings is eating up by the "must have" maintenance and cleaning of these units...you don't clean them the efficency drops way down...way down.Average (household)savings on your gas bill is less than $200 a year,average fee for a yearly cleaning and service $300-$400.oh yea they also cost 4 times more (unit plus install)than a tank.