Rotten Egg Smell
Occasionally, customers express concerns of a "rotten egg" type odor from the water. The smell of rotten eggs is usually associated with hydrogen sulfide. Hydrogen sulfide is formed by sulfur bacteria that may occur naturally in water. Those bacteria use the sulfur in decaying plants, rocks, or soil as food or energy source and as a by-product produce hydrogen sulfide gas. The sulfur bacteria do not cause disease, but their presence in water can cause a bad taste or odor.
Faucet or Drain?
When people call about hydrogen sulfide odor, they often times state the odor is coming from the kitchen faucet. What may be occuring is that food has accumulated in the drain of the kitchen sink and is decaying producing the hydrogen sulfide gas. When the water is turned on, the water displaces the hydrogen sulfide that has accumulated and the gas rises making the odor more noticeable. Because turning the water on initiates this sequence of events, people understandably think the odor is coming from the water.
In order to determine if the odor is truly in the water, it is suggested that a person draw a glass of water and walk away from the sink then smell the water. This way, someone can decipher if the sink or the water is the source of the odor.
Eliminating the Odor
If the sink is the source of the odor, pour bleach down the drain and let it sit for a few hours. This should eliminate any sources of odor. Repeat as the problem reoccurs.
Hot Water Heater
"Rotten egg" odors from hydrogen sulfide are sometimes only present in hot water. This may indicate a reaction with the magnesium rod in the water heater. Consider either removal or replacement with an aluminum rod as a remedy.
If the temperature in a hot water tank is set to low, odor causing bacteria may thrive which results in the hydrogen sulfide odor. Raising the temperature to 140 degrees Fahrenheit for two hours can kill the odor causing bacteria (make sure you have a properly functioning pressure relief valve or let the hot water drip out of a faucet before turning up the temperature). Upon completion, return the temperature to the desired leve.
Occasionally flushing the hot water heater can also help to remove the odor causing bacteria as well as sediment that may be adversely affecing the efficiency of the hot water heater.