If your well water has a rotten-egg smell, you have sulfur in your water. Using an iron and sulfur eliminator, which is a type of water filter, the odor can be eliminated. However if the pipes are old the water will often become contaminated again as it flows through the pipes. To prevent this problem you can add a city water maker. This will put a tiny amount of chlorine into the water so it taste and smells exactly like city water.