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Q. I recently lost my power for 30 hours during a storm, and the following day, my hot water had a bad odor to it. I did as you suggested in your article, and raised the temperature to 140ºF. This seemed to solve the problem, but I have a few questions to ask you about it. Would it be more energy-efficient to leave the temperature at 140ºF and use less hot water to bathe or shower, or to lower the temperature back to 125ºF, where it was originally and require more hot water? Also, would the hotter temperature have an adverse effect on my heating elements? And, since my dishwasher draws all hot water, would the elements in it be damaged?
A. That record setting storm we had a few weeks ago was one of those rare long rain events without a given name (like say, Agnes or Floyd) that had, for many, far reaching consequences such as fallen trees, flooded basements and extended power outages. The majority of my time since then has been devoted to trying to resolve water issues in houses that have stood for generations bone dry but no longer.
The rotten egg odor that came out of your water heater after the power came back on and your well was able to produce water again was from bacteria. The amount of rain we had did cause some groundwater to enter some driven wells and whether or not the bacteria was in the well before the storm one thing is clear, it’s there now. After TS Isabel the Anne Arundel County Health Department ran a very well done public service spot on the public access cable TV showing homeowners how to “shock” driven wells with bleach as so many well heads in the County were inundated by filthy storm waters. Some wells after this past storm would benefit from such a treatment. I found printed directions on their website @ http://www.aahealth.org/a2z.asp?ID=24. If you’re uncomfortable disinfecting your well with bleach yourself, any plumber or water treatment type can assist you. Remember if there is any bacteria residing in your potable water system it will stay there until something is done to remove it. And that includes each and every pipe and fixture. You can have the water lab tested and they will be looking for an unnoticeable marker organism but the smell is enough for you to prove the point. They’re there. The smell producing bacteria type is called SRB (sulfate reducing bacteria). They produce Hydrogen Sulfide gas(H2s) and even low levels of it can create the odor especially from hot water. Some will recommend removing the water heater’s anode which will frequently do the trick. That voids the water heaters manufacturer’s warranty and may shorten the life of the tank itself. The SRB are not considered harmful-- just annoying. The elevated temperature method I wrote about wasn’t just for SRB but it works as you saw. Lower the temperature and the smell will return. Some sources I’ve seen recommend running the temperature to 160ºF for a while-- a couple of hours-- then turning it back down. When I built restaurants the health departments wherever I worked wanted the water heater set and left at 180ºF for dishwashing. Water heaters until about 1990 were factory set at 140ºF. The lore as I learned it was that the suppliers of residential dishwashers needed water that hot to get the dishes clean. There was a scalding lawsuit against water heater makers and the manufacturers reduced the factory pre-set to 120ºF. Modern dishwashers have their own water heating capacity so line water temperature isn’t a critical as it once was for clean dishes. In the mid-1990s just after the newer lower setting went into force, I called a few plumbers and asked the simple question “What temperature do you set your water heaters when you install a new one?” Not one mentioned a number below 140ºF and reason for that was after a homeowner had been on a heater putting out 140ºF until it died, the new 120ºF degree water didn’t feel as hot and some complained and plumbers hate call-backs. 140ºF temperature won’t hurt your dishwasher and I don’t feel will aversely impact the heater element life to any significant degree. Energy consumption aside, a great number of organisms that can survive in 120ºF water can’t survive in 140ºF. Legionella, for example, can’t live in water 131.9ºF and higher. But with well water, the best first line of defense is installing a UV light on the water line past the pressure tank. It will eliminate 99.9% of the waterborne organisms that pass it and that’s good. They cost about $400. and are worth every penny.*end