External Rust but No Water Leak - Time to Worry?

[whitpet]

I've got an AO Smith electric water heater about 8 1/2 years old; warranty was 6 years. It sits in a plastic drain pan, but I've never seen any water in the pan except a little bit that escapes when I flush the tank once a year. I have just begun to see a little rust on the very bottom curve of the tank, where it touches the drain pan, but there's no water present. (See photo below). Most of the rust discoloration in the photo is actually on the drain pan, and it is dry. I removed the element access cover, but a styrofoam border is sealed in place, so I could not check for the presence of any water between the outer cover and the holding tank.

I live about 6 miles from the coast, so rust is a common issue. Is this a sign of impending doom? I'm not real excited about replacing it, but I guess I'd rather do it a little too soon than wait too late. If I wait too long, what are the chances I'll get a catastrophic failure, rather than a slow leak? It's in a garage so I can deal with a small leak, but I travel a good bit with work so a major burst is a problem.

Thanks for any feedback,
Whit

[Gary Swart]

I suspect the rust is just external and is not cause for immediate concern. Even when it does rust out, it will not let go all at once. You will have a small amount of water long before the bottom falls off. I'm not saying to forget about it, but just don't be in a rush to get a new heater.

[whitpet]

Thanks for the feedback; that's reassuring. I'll keep an eye on it and watch for water. Thanks again for your help.

[hj]

Pry the rim of the bottom out and see if there is water inside it. The only time you can be sure the heater is leaking is when you do see water. Many times it can leak and then rust closed before any damage is done. I have removed the jacket from leaking heaters and the tank would look like it had been shot with a machine gun, there were so many rust spots which had sealed themselves.

[Cass]

Catastrophic failures are extremely rare... I personally wouldn't concern my self with thinking about it....

[whitpet]

Thanks for all the advice from the pro's. The prying part made me nervous, but I was able to slide a piece of paper between the bottom rim and outside cover at a number of places, and it came back dry. Not absolutely sure it got all the way to the bottom, but I think it did. I'm gonna watch it for awhile. I'll be back if water shows up.

Sure wish I could BOWDLERIZE that $%&*#^% rust.

[hj]

Why should the "prying part make you nervous"? All it is is some sheet metal. It has absolutely NOTHING to do with whether the tank is, or will, leak.