Water that Stinks

(Diagnostic steps to finding the source of the smell so you can correct the problem) 

My Water Stinks!

Water containing hydrogen sulfide gas, can be, but is usually not a health risk. However, it does impart a nuisance “rotten egg” odor and taste. Water with as little as 1.0 p.p.m. (part per million) hydrogen sulfide can be corrosive and may tarnish copper, silverware, etc. Occasionally a black material is released causing laundry stains.

Hydrogen sulfide is formed by sulfur bacteria that appear naturally in water. These bacteria use the sulfur in decaying plants, rocks, or soil as their food or energy source and produce hydrogen sulfide as a by-product. The sulfur bacteria do not cause disease, but their presence in water can cause a bad taste or odor. Note: You may be able to taste hydrogen sulfide in your water even when the concentration is quite low.

Discovering the Source of the stink

The ideal time to isolate the smell is after you have been away from home for a few hours. This allows your nose to become sensitive to “that” smell again.

Begin with an outside faucet. . . one with water flowing untreated directly from your water source. Let it run a minute or two and then smell it. If you detect an odor, you have discovered “the” source or one of the sources. If there is no odor, you’ll need to look a bit further. 

Next Step. . . Turn on a cold water faucet inside the house and let it run a minute; now smell. If you detect an odor there must be a device such as a cartridge filter, water softener, water heater (more on water heaters below), etc. connected to the water line needing attention.  Replacement of the filter cartridge and/or cleaning and sanitizing the offending equipment should “cure” the problem.

If it is a Cartridge Filter; simply sanitize the inside of the housing with a disinfectant, such as a 50% mixture of unscented bleach and water, and replace the filter element with a new one. If the odor is coming from your Water Softener, call the company where you purchased the unit for guidance.

You Can Do It Yourself! A water softener can be sanitized by pouring Hydrogen Peroxide or Chlorine Bleach in the brine well of the salt tank and starting the regeneration cycle. Prior to taking this action; check with the seller or manufacturer for a recommendation on the concentration and amounts for your specific softener.

The Next Step… If your cold water doesn’t stink, turn on the hot water and let it run a few minutes. “Rotten egg” odors from hydrogen sulfide are often present Only in hot water. This may indicate a reaction with the magnesium rod (anode rod) in your water heater.

Note: The anode rod is a sacrificial metal part used to protect against corrosion in a hot water heater. Consider permanently removing the anode rod or replacing it with an aluminum rod. *Removing the anode rod may void your water heater warranty. **Very Important! Turn off the incoming water valve and allow your hot water heater to cool prior to removing the anode rod.

Sometimes hot water will have a “sour” smell, similar to the smell of an old damp rag. This happens most often when, in an effort to save energy, the water heater thermostat setting has been lowered. Odor-causing bacteria live and thrive in warm water and can “happily” infest a water heater. This is corrected by returning the thermostat to the manufacturer recommended temperature. Odor-causing bacteria are killed at higher water temperatures (at or above 140 degrees (60’ C).

Caution: Be sure the water heater has an operable pressure relief valve before increasing the water temperature. If you want to keep your water heater temperature at a lower setting because scalding from hot water is a concern, each time the odor returns, increase the water temperature for a few hours to kill the odor-causing bacteria. Then flush the very hot water out of the tank and lower the temperature back to the desired level.

Legionnaires Disease Warning:

Legionella bacteria are found naturally in the environment, usually in water. The bacteria grow best in warm water; as found in hot water heaters (and hot tubs). *This is another good reason to keep your hot water heater at 140 degrees (60’ C) minimum.

It’s my Source Water that Stinks. What can I do? 

If the odor is not very strong (and there is no iron in your water) you may be able to solve this challenge with a Carbon Cartridge Filter installed on the cold water line where you get your drinking water and a Carbon Shower Filter in the shower. A much better choice would be a 20” X 4 ½” Whole-House Carbon Filter on your incoming water line to filter all of the water entering your home.

Important! Carbon filters must be sized correctly. If water runs through the filter too fast the odors will not be removed. This is part of the reason faucet mounted mini-filters are ineffective. Larger-sized filters are more effective in removing odors as well as other contaminants.

It is VERY Important to replace the carbon filter cartridge and sanitize the housing on a regular basis.  Carbon filters may need to be changed every 3 – 6 months and can last up to one year. Carbon filters provide a perfect place for bacteria to grow and reproduce. Regular filter replacement helps prevent buildup of bacteria in the filter cartridge as well as insuring effective odor removal.

For those of you with Mini-Filters on your kitchen faucet, ice makers & water dispensers in your refrigerator… you should replace those filters more often than the manufacturer recommends for the reasons mentioned in the previous paragraph.

My water has a Strong, Rotten-egg smell. . .

Strong, “rotten-egg” odors in untreated water are often the result of the decomposition of underground organic deposits. As water is drawn to the surface, hydrogen sulfide gas may be released. When concentrated; this gas is flammable and poisonous. It can be toxic to aquarium fish. Reminder: You may be able to taste hydrogen sulfide in your water even when the concentration is quite low… in other words; “Taste” is not a good indicator.

If the “rotten-egg” odor of your untreated water is very strong, you are well advised to seek the assistance of a water treatment professional; one familiar with water quality in your area.

There are three basic ways to solve this problem:

1) Filter it

  • A Whole-House Filter filled with hydrogen sulfide specific removal media is one choice. However, it can be challenging to correctly size these filters and the filtering media can be VERY messy.
  • A Whole-House Carbon Filter (or series of carbon filters) is most often, a better choice… again, assuming there is very little or no iron in your water.

2) Chlorinate it – A “chlorinator” injects small amounts of chlorine into the incoming water. The chlorine quickly reacts with the hydrogen sulfide to form a tasteless, odorless, yellow particle. The yellow sulfur particles remaining in the water can form a yellow film on clothing and fixtures.

A quality backwashing filter will remove sulfur particles. A chlorine injector, coupled with a backwashing filter, and an activated carbon filter to remove the chlorine is an effective combination. Note: Chlorine injectors need regular attention; adjustment and refilling. Quality backwashing filters are self-sufficient, requiring little or no maintenance for many years. Carbon filters need to be replaced at least annually.

Remember, when you mix chlorine with organic materials the chances are trihalomethanes (THM’s… possible cancer causing carcinogens) will be formed.  Be sure the carbon filter(s) you choose is/are high quality and designed for chlorine removal.

3) Aerate it – An aeration system sprays the incoming water into the air, draws fresh air through the spray and collects the aerated water in a storage tank. The aerated water is then pressurized and filtered. The air drawn though the spray must be vented outside the house as it can be both toxic and explosive.

The primary advantage to this system is that no chemicals are added to the water. This type of system is relatively low maintenance but the initial investment is higher. And of course, you’ll need to find room for the storage tank and equipment. Note: Storage tanks are notorious for breeding bacteria. A ultra-violet light system installed in the storage tank outlet piping is highly recommended. 

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