News

Aug 04, 2023

On the Level: Addressing the hot water heater's 'rotten egg smell'

We remember your article about raising the hot water temperature in the water heater to eliminate "rotten egg" smell. Now it is worse - if that were even possible. It all started when we bought a new

We remember your article about raising the hot water temperature in the water heater to eliminate "rotten egg" smell.

Now it is worse - if that were even possible. It all started when we bought a new water heater.

Water treatment people say take out the anode rod, but our plumber says that will severely shorten the life of the heater. Others say to use bleach.

Any thoughts?

Without you telling me, I'll bet you're on well water.

Your plumber is correct that the result of pulling an anode from a water heater can shorten its life. Anodes are there for a reason, but can contribute to your problem, depending upon the aggressiveness of your well water.

The adage about stinky hot water used to be that if the water heater has an anode rod, remove it; and if it doesn't have an anode, add one.

Pulling an anode rod out of any water heater - or adding or replacing one - can be quite a chore depending upon the amount of free space you have above the water heater. Anode rods don't like to be bent. That's a job that potentially entails emptying the water heater, and disconnecting pipes and wiring in order to tilt it on its side to get the rod out. So let's try something else.

If you haven't tried setting the thermostat up to above 140 degrees, try that. Water heaters used to come preset at 140 straight from the factory.

I believe the logic for that setting was when automatic dishwashers became so prevalent in housing, manufacturers wanted water that hot to work with the detergent to get the dishes clean. Now dishwashers heat their own water, and but they took the phosphates out of the detergents, so getting really clean dishes is still a challenge.

Along came a scalding lawsuit in the early 1990s that went against the water heater manufacturers, and they began putting big warning labels on the water heater jackets much like McDonalds coffee cups after their own scalding problems. The lawyers stepped in and said to lower the temperature along with the warning, so now water heaters are shipped from the factory preset at 120 degrees. A few minutes exposure to water that hot will hurt you too.

My problem with storing water in volumes of normally 50 gallons for hours on end waiting to be used at 120 degrees is at that temperature many micro-organisms can not only survive but thrive. Your water heater is an example.

The bacteria creating the smell is sulfur-reducing bacteria, and they don't survive at higher temperatures. Legionella bacteria can survive in water up to 131.9 degrees, and they don't smell, but can make you sick or worse.

Shocking the water heater with chlorine (bleach) will work, but only temporarily. Once the chlorine is flushed from the water heater through use, the conditions return for the bacteria to thrive, and they will come back unless you head them off.

You can do that in one of two ways. Up the thermostat setting as you chlorinate, or while the chlorine is going into the water heater you place a UV-C sanitizer light on the water supply. They cost in the upper $400 range and will kill 99.9 percent of the bacteria that passes it. But it won't kill the bacteria already in the water heater tank, so you'll need to address that separately.

I've been a big fan of the UV-C lights since they first came into wide residential use decades ago for well water supplies. I recently read a story reporting that showerheads can harbor bacteria. The report didn't surprise me, but I noted that the report pointed to municipal water supplies and reported not finding their target bacterium M. Avium on well water supplies, but plenty of other types bacteria on rural showerheads. The bacteria in the study doesn't make healthy people sick, but those on the fringes can be sickened. I'll bet a UV-C sanitizer light would reduce or eliminate the incidence of this bacteria and in doing so open a new market for the lights.