Knowing exactly which type of odor problem you have can save you the time and hassle of trying to guess what steps you need to take.

Minor, Musty Smell

You might be able to solve this minor problem with a small, point-of-use carbon filter, or a whole-house filter on the incoming water line. The smell will attach to the carbon particles, which will keep it from traveling into your usable water supply. Remember to change the filter so that organic bacteria cannot grow inside it.

Strong, Rotten Egg Smell

This problem is usually caused by the decomposition of decaying underground organic deposits , or sulfur-reducing bacteria. As the water is drawn to the surface, hydrogen sulfide gas can be released. This gas can be flammable and poisonous in high enough quantities.

The sulfur-reducing bacteria can also generate slime that will promote the growth of other bacteria. This can clog pipes and wells. The hydrogen sulfide gas can cause black staining on silverware and plumbing fixtures.

How do I determine the source of the rotten egg smell?

First, leave all water taps in your home alone for a few hours before testing. Next, run the water separately from both the cold and hot water taps:
-If the smell is only from the hot water tap, the source is likely to be the hot water heater
-If the smell is from both hot and cold water taps, but only from water that is treated by a water softener, then there may be sulfur-reducing bacteria growth in your water softener.
-If the smell is from both hot and cold water taps, but goes away the longer you run the water, you may have sulfur-reducing bacteria in your well or piping.
-If the smell from both taps is persistent, you might have hydrogen sulfide gas in your groundwater.

Strong, Musty Smell

If you have this situation, look for a local company that has experience in dealing with this problem. There are a few ways to solve it:

Filters

Installation of a whole house filter loaded with a media that is specific for hydrogen sulfide removal. These types of filters must be recharged with chlorine or potassium permanganate. The removal capacities of these types of filters are usually fairly low. They need to be sized to contain enough media to prevent premature exhaustion, and subsequent passage of the smell, to service. It is also typical that the amount of hydrogen sulfide can fluctuate rapidly, causing great difficulty in sizing the unit. In addition, potassium permanganate is extremely "messy", and will leave stains that are very difficult to remove.

Feeders

Feeder systems consist of a small pump that injects small amounts of chlorine (usually) into the incoming water. The water must then be held for a short period of time to allow the hydrogen sulfide to precipitate out of the water. This tank should be designed in such a manner that when water enters, it will mix thoroughly with the water in the tank, to assure complete reaction. The water should then pass through a filter to remove both the precipitated matter and the remaining chlorine. Be aware, however, that when you mix chlorine with organic materials (remember where hydrogen sulfide come from!), the chances are very high that trihalomethanes (possible cancer causing cragginess) will be formed. Also, feeder maintenance is high. You should be prepared to "play" with the unit frequently.

Aeration

Aeration consists of breaking the incoming water into small droplets (spray) into the air, drawing fresh air through that spray, collecting the water into a storage tank; re-pressurize the water, passing it through a particulate filter to catch any particles that might be carried out of the storage tank. The air drawn though the spray must be vented outside the house, remember it is toxic and explosive. Although this system necessitates another pump to re-pressurize your supply, you are not adding any chemicals to your water, which makes it attractive. This system is low maintenance and no chemicals to purchase. Initial cost may be higher, however, and space requirements may be greater.

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