What if my water has a rotten egg odor to it?

In most cases, the odor is present only when the water is first turned on or when hot water is run.  If you notice this smell in your drinking water, it probably contains hydrogen sulfide (H2S) gas.  Hydrogen sulfide gas produces a strong and unpleasant “rotten egg” or “sulfur” odor and taste.  Sulfur, sulfates and hydrogen sulfates are naturally occurring minerals in our groundwater and are not generally considered harmful because the taste and odor is so unpleasant at such low levels that the taste and smell would prohibit most people from drinking it well before it reached harmful levels.

Water heaters can produce hydrogen sulfide gas by providing a warm environment for sulfate-reducing bacteria to live.  Heat forces the gas into the air which may cause the odor to be especially offensive in a shower.  Also, the magnesium anode in the water heater supplies electrons that sustain the reaction of sulfate to hydrogen sulfide gas.  One of the simplest things you can do if your water has an odor is to check the temperature setting on your water heater.    Hydrogen sulfide gas builds up in the water heater when the water doesn't get heated to a high enough temperature to burn off the gas.  Builders and realtors often drop the temperature down to the lowest setting, to save on the heating costs before the home is occupied.  Here’s what you can do:

  • Turn the heater up to the highest temperature (or above 160 degrees if it has the temperature setting) for about two hours.   This will heat the water high enough to ‘burn off’ the hydrogen sulfide and have it vented away.
  • Turn it back down to a mid-range temperature that you want to use on a daily basis.
  • Within about 48 hours the smell should be totally gone.

You may actually use less hot water this way because the temperature is regulated by mixing with more cold water at the showerhead or sink tap.

Show All Answers

1. What is the water hardness level?
2. What is the pH level of the city’s water?
3. Is my private well water tested by the City?
4. How do I know if there are any water restrictions in place?
5. What causes discolored or cloudy water?
6. What should I do if my water is cloudy or discolored?
7. What if my water has a rotten egg odor to it?
8. What if my water has a chlorine smell to it?
9. How and why should I flush my hot water heater?