If you discover an unpleasant “sulfur” or “rotten egg” odor in your water, there are three primary factors that cause it. The first is a natural & harmless water-born gas called hydrogen sulfide (H2S). Hydrogen sulfide is commonly present in most groundwater wells, both deep and shallow. Although there is no known risk to your health, hydrogen sulfide can be an aesthetic irritant.

The second factor that can cause this odor is lack of movement in the water distribution system causing it to become stagnant. This lack of desired turn over can happen as the result of obsolete infrastructure or lack of customer usage in the winter season. The longer that water remains in the distribution system, the more likely it is to develop an odor. When both of these situations are combined, the odor is most noticeable.

The third factor that can easily cause a rotten egg odor in your water is the improper maintenance of your hot water tank. Equipment manufacturers recommend that you flush your hot water tank at least once every three months, but it depends on how much hot water you use in relation to the size of your tank. For example, a large hot water tank with moderate usage will require more frequent flushing. If this is not done, the water in the tank can become stagnant in a similar fashion as the second factor. As you draw from the tank, the stagnant water travels through your plumbing where the odor can be noticed on the receiving end. Another problem with hot water tanks that can produce the most pungent sulfur smell is a magnesium heating element that’s going bad. When the magnesium rod begins to fail, it is designed to produce this odor as a warning that you need to replace it soon.

If you are experiencing an odor problem in your water, the source of the problem can be identified through a simple test at your kitchen sink. If you notice the odor while using hot water, or any blend of hot and cold water, this indicates a problem with your hot water tank. In most cases, this can be solved by a simple flushing. If you notice the odor solely in the cold water, with no hot water blend, this indicates a problem in the local distribution system. If this is the case, contact the Water Division of the Public Works Department at 847-960-7500. Just like the way a hot water tank needs to be flushed, the local water mains in your area may require the same.