Rusting Water Heater


Please take a look at these 2 gas water heater pictures. In the first picture you can see rusting along the bottom exterior. In the second picture you can see about 1/4" of rust flakes on the top of the burner and that the bottom of the water tank is rusted. I’m trying to figure what to say about this. At a minimum the rust should be cleaned out and off of the burner (serviced). The water heater isn’t leaking. Should I say that this water heater should be replaced? Or that a plumber evaluate it? It’s 13 years old and still works, but looks like it could spring a leak any day now. Thanks for your help.



I think you just said it…

Although the water heater isn’t leaking presently, it has rust on the burner and the bottom of the tank is showing rust. I recommend replacing the water heater ASAP to prevent leakage and damage resulting from the leakage.

If it isn’t leaking how did the rust get there?? And the water stains on the floor???

I see the stains. I’m not sure how they got there. Could of been the t+p valve released, someone opened the drain valve, or a leak. I will mention the water stains too. I’m not sure about all the rust. The room doesn’t have a cooloing or heating source. Could be condensation/high humidity. Thanks!

  1. There are a wide variety of residential water heaters that range in capacity from fifteen to one hundred gallons. They can be expected to last at least as long as their warranty, or from five to eight years, but they will generally last longer. However, few of them last longer than fifteen or twenty years and many eventually leak. So it is always wise to have them installed over a drain pan plumbed to the exterior. Also, it is prudent to flush them annually to remove minerals that include the calcium chloride bi-product of many water softening systems. The water temperature should be set at a minimum of 110 degrees fahrenheit to kill microbes and a maximum of 140 degrees to prevent scalding. Also, water heaters can be dangerous if they are not seismically secured and equipped with either a pressure/temperature relief valve and discharge pipe plumbed to the exterior, or a Watts 210 gas shut-off valve.

  2. There are rust particulates within the combustion chamber, and smothering (or covering) the burner, which should be removed.

  3. There is rust on the outside of the water heater tank. Typically rust can occur due to condensation, or in the presence of a leak. While there was no active leak at the time of the inspection, one could have occurred in the past, and could again.

  4. There is evidence of hot combustion gasses escaping from the combustion chamber. This is typically known as ’ flame roll out’ and is an obviously an unsafe condition. Due to these issues, we recommend evaluation and/or service by a licensed plumber

Water temperature of 140 degrees will burn in less than 5 seconds.

I recommend the heaters be set at 120 degrees or less for enhanced safety.


As for the water heater in the pic, it shows indications that it will require replacement now or in the very near future, IMHO.

the rust in the burner compartment is normal, but should be cleaned out. i just cleaned an almost 2 inch pile of rust off of the top of the burner in my heater. the rust is the result of condensation forming on the heat exchanger causing it to rust and flake off and fall on the burner. this is perfectly normal, and more likely to happen in homes that have a very cold water supply.

The rust on the outside of the cabinet is not normal at all and definitly needs to be looked at. also it looks like flue gasses were spilling from the combustion chamber

I’m no expert, but condensation in the burner/heat exchanger compartment is a result of inadequate combustion and/or venting (A hazard) regardless of supply water temperature.

Results of venting and combustion issues/problems as well as serious safety/health concerns (CO) are represented with this water heater.

Whether it’s leaking or not is the least of this units worries.

I agree with William on the improper venting.
Condensation from a defect in the flue is likely.

Recommending further eval/service on a heavily rusted
13 year old water heater is prudent.

Craig, do you live in a humid climate? In dry Colorado, any water heater with 1/4" of rust on the burn chamber floor would have lived most of it’s life already.
Poor combustion along with backdrafting for #1.