The treatment options for odor varies with the source and the concentration of the odor.

Aside from chlorine odors, most odors on municipally treated water, are a result of decaying organic material and algae in source water, from decaying or contaminated distribution lines, or from water heaters in the home.

The most common odors we have encountered from private water systems are typically the result of microbial activity, or compounds of iron, manganese or sulfur. For instance hydrogen sulfide commonly occurs in well water as a result of decaying organic matter and the activity of sulfur and iron bacteria.

To solve an problem, the first step is to identify whether the odor is in the source water, or whether it is being created in your piping or water heater by microbial action.

Is the odor in the cold water outside the house, (run a hose bib)? If this is the case, your source water may actually contain the odor, and depending on the situation, you may be able to filter the water as it flows in to your house or building. If you are on chlorinated city water and your water from an outside hose bib has a strong chlorine odor, then an activated carbon system may remove the odor. If you have a rotten-egg or sulfur odor from city water, identify whether it is just the hot water, or if its also cold water, and whether or not the odor exists inside or outside the house, say from an outside hose bib or faucet.

If the odor is in the cold water inside your house or building only, then you map have aging galavanized iron piping, or some part of your plumbing contains iron piping. Various strains of iron bacteria live in iron piping and give off methane and hydrogen sulfide gas as they decay, causing the odor. These same bacteria often thrive only in water heaters (yes even new water heaters!) regardless of the type of piping you have. For this type of problem, you cor your plumber can add a couple of cups of bleach to the water heater. Let the hot water run until you smell the bleach. Let the water heater sit for several hours. This will usually eliminate the odor. If the odor returns in a few days or few weeks, then one would have to have a plumber replace the magnesium anode rod inside the water heater with an aluminum anode rod.

The incidence of “rotten egg” sulfur odors and often the resulting black water in hot and cold water lines is due to the reaction of sulfates and microorganisms in water. This can occur in the well directly, or in the household plumbing both hot and cold water pipes, or in only the water heater and hot water lines. Some well waters contain an excessive amount of sulfates with various strains of sulfate bacteria. These bacteria, harmless to health, will react in stagnant water that has been depleted of oxygen, and will produce hydrogen sulfide gas. Almost all water heaters have “anode rods” which in a cathode-anode reaction, produce excess ions that wear off the anode rod and adhere to the inside glass lining of the water heater, preventing corrosion. These bacteria (typically the “desulfovibrio” or a related species) can be killed with adequate amounts of chlorine by periodic shock chlorination, or by continuous ozone or chlorination.

If your well water is used directly from the well, and not aerated in a atmospheric (non-pressurized) storage tank, then the odors are most likely caused by anaerobic bacteria. These types of bacteria thrive in oxygen-deprived environments, and often on waters high in sulfates. If the cold water entering the home contains no odors, odor can still develop in cold water piping in the home, especially in galvanized iron piping. Often iron piping in the house is of an older age and can be corroded, providing a good environment for the bacteria to grow and odors to develop. If there is an odor in the cold water inside the home, but not directly from the well, see if the piping is iron piping, and then replace it with copper. As a first step to this process, one can shock-chlorinate the piping and sanitize it, and see if the odor can be eliminated.

The most common methods to eliminate odors from well water are:
• Periodic shock chlorination with high doses of chlorine
• Aeration of the water to oxidize the hydrogen sulfide gas, combined with periodic shock chlorination.
• Continuous ozone injection to the water
• Continuous chlorine injection to the water
• Filtration of the odor by greensand media or activated carbon
• Injection of hydrogen peroxide