Why does my water smell like rotten eggs?
The "rotten egg" smell that may come from your faucet is likely hydrogen sulfide. Hydrogen sulfide (commonly called sulfur) odors sometimes are present in water fixtures of homes and businesses. Sulfur is a mineral that exists in nature and is commonly present in water supplies. So long as sufficient oxygen is present, it exists in a combined form with oxygen and does not present odor problems. However, in the absence of oxygen there may be conditions present which convert the combined oxygen form with a form combined with hydrogen (ie; hydrogen sulfide) instead, creating a compound that has a characteristic rotten egg odor. Even though this odor is a nuisance, the water is safe for consumption. While this is of no comfort, the phenomenon is random and found across the nation.
What does the city do to alleviate the odor?
In addition to all the other standard protocols required of a safe drinking water system, the city often boosts disinfection stations as needed throughout town and cleans the water distribution pipelines with high velocity flushing.
Why does the cold water smell like sulfur as well as the hot water?
Chances are you smell the remnants of the hot water, and if you allow the cold faucet to run longer, the odor should disappear. Your outside faucets are plumbed directly to cold water, and there likely will not be a sulfur smell on those faucets. That will help you to determine if the source is your water heater.
What can I do to help control the odor?
There are several different steps you can take to help alleviate the odor. If the odor only occurs on the hot water side, the first thing to try is to turn on the hot water throughout your home and let the water run until cold. Doing this flushes out the water heater and may eventually lessen the odor. You may have to do this more than once, and you may need to do it periodically to keep the tank flushed out. It may also help to increase the temperature of the water temporarily for several hours before flushing (be careful of scalding temperatures at the hot water fixture outlets while the temperature is turned up).
Another thing you can try is to have a plumber remove the magnesium corrosion rod from your water tank and replace it with an aluminum rod. The factory installed magnesium rod in water heaters causes the dissolved sulfur to precipitate into a gas, causing the odor at the faucet.
If the odor is on the cold water side or both, it may be caused by the establishment of a condition in the plumbing system that causes the conversion to the hydrogen form. Usually this is limited to one or a few fixtures where certain bacteria have become established (known as sulfur reducing bacteria). Resolving this issue is often more difficult, requiring a qualified plumber to disinfect the home water system (usually with a chlorine solution), followed by a through flushing to remove all the disinfectant.
What if the odor doesn’t go away?
Please feel free to contact Environmental Services (972-237-8055) or Water Utilities (972-237-8400) and someone will contact you to discuss the specifics of your issue. Even though we won’t be able to enter your home and work on your plumbing, we will gladly discuss the issue with you and provide you with as much information as possible on how to alleviate the odor.
Is city water safe to drink?
Public Works takes all measures necessary to provide city residents with safe water that is free from objectionable odors, tastes, and color. In addition, the Environmental Protection Agency and the Texas Commission on Environmental Quality set stringent levels of regulation for public water supplies. Daily, monthly, quarterly and annual water samples are monitored. Please see the annual water quality report for details on what parameters are tested and the lab results.