There are several issues that may be causing that “rotten egg” odor in your water.
Hydrogen sulfide gas (commonly referred to as “sulfur”) is a contaminant that we find regularly in well water. Sulfur can make water smell and taste terrible. It results from decaying organic matter and is one of the well water contaminants that homeowners fear most. With modern technology sulfur can be effectively removed from your water. Sulfur gas is corrosive. The gasses, when released from the water, tend to cause damage to copper plumbing, jewelry, HVAC components, and electronic devices. Because hydrogen sulfide is a gas, it is imperative that the water be tested at its source.
Some types of bacteria, while not necessarily harmful to your health, can cause serious odor problems. Often times, these problems can be remedied with a simple well disinfection. If a well disinfection fails to eradicate the odor, continuous disinfection may be necessary.
Water heater rods
Water heaters are often equipped with anode rods that are designed to minimize tank corrosion. In some situations, the rods react poorly with well water and create a terrible odor and sometimes discolor the water or create stains in the home. These rods can be replaced with rods made from different alloys that are less likely to cause odor issues.
The best way to determine what is causing an odor problem in your water is to have the water tested and to consult with someone who has experience diagnosing and solving water odor problems.