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How To Treat Sulfur Odors In Well Water

Does your water stink like rotten eggs?  Are you trying to find out how to treat sulfur odor in well water?  Do you ever say “my tap water smells like sulfur”, or “my hot water smells like sulfur”?

Follow these steps to rid your home of these smells.

First Check For Odors in Cold & Hot Water

The first step is to find out if the odor is from hot water only, or is also from the cold well water.

Run a hose bib or tap as close to the well as possible and fill a 5- gallon bucket or other container and notice if there are odors.

If you smell a “rotten egg” odor, this is hydrogen sulfide gas. If the water smells like oil or asphalt this can be from manganese. If your water smells like cucumber or sewage this is usually a result of iron and/ or sulfur bacteria.

Run the water hot water from each tap and notice if there is an odor in the hot water that is not apparent in the cold water.

If there is only an odor in the hot water, this indicates a problem with the water heater. Iron and sulfur bacteria can interact with the anode rod in water heaters, resulting in hydrogen sulfide gas only in the hot water. Changing the anode rod to an aluminum rod can often solve this problem.

Next Thing to Do: Test Your Water

If there is an odor problem with the water supply, the first step is to determine the source. If the source is from the well, a general mineral water analysis is critical to select the right system to treat the problem.

The test should include analysis for pH, iron, manganese, hardness, total dissolved solids at a minimum. Other tests for sulfate, hydrogen sulfide and tannin are recommended as well.

Take the sample as close to the well as possible. With these results, you can identify the best type of water treatment to use, and what type of system to select, based on your water chemistry.

For health-related issues, your well water should be tested for total coliform and e-Coli (fecal coliform). If infants and children will be drinking the water, a general mineral, metals and a bacteriological test is recommended.

If the source of water is a public water system and you have problems with odor, it is important to contact a utility official to determine whether the odor is from the public system or the home’s plumbing or piping.

Top 6 Ways to Eliminate Rotten Egg Odor

1. Shock your well with chlorine bleach or hydrogen peroxide to get temporary relief from sulfur odors. Often keeps odors away for 1 – 2 months.

2. Chlorinator: Install a chlorine injector system (chlorinator) on your wellhead for continuous injection of chlorine when the water is running. Chlorination eliminates the sulfur bacteria that cause the odor, and combined with an Air Charger self-cleaning backwash carbon filter can eliminate odors continuously and take out chlorine residual before the home.

3. Peroxide: Install the same system as a chlorinator but use hydrogen peroxide in place of chlorine bleach, followed by backwashing catalytic carbon filter. Unlike chlorine, no residual salts or residues are left in the water after water flows through the carbon system.

4. Air Charger Carbon Filter: Install an Air Charger Catalytic Carbon Filter. No chemicals are needed, however, the system also can inject peroxide to make the catalytic carbon last longer. No filter cartridges to change, carbon lasts for several years and is easy to change out.

5. Air Compressor Tank Aeration System: This injects a lot of air under pressure and can eliminate odors under certain conditions.

6. Ozone Gas: Expensive but can be very effective. Inject ozone gas under pressure to quickly eliminate sulfur odors

See our section “Odor Systems” for filters and systems to remove odors from well water.

How To Treat Sulfur Odor in Well Water:

water heater odor killerONE:   If you have sulfur odor only in both cold and hot water, and no iron or manganese (rust, red or black staining) the best option is to use an Air Charger Carbon Filter with peroxide cleaning kit (which comes as an option).

TWO:  If you have extreme sulfur odors from the cold well water, we recommend shocking the well with chlorine and then installing a peroxide injection system with a backwashing carbon filter (see below).

THREE:  If you have a rotten-egg sulfur odor in the hot water only, we recommend installing a Water Heater Odor Killer.

Use a Chlorinator or Inject Hydrogen Peroxide to Kill Odors

well water chlorinator diagram










  • Use 5% grade liquid bleach or 12% liquid pool chlorine OR 7% hydrogen peroxide.  The same system can inject either bleach or peroxide.
  • The precise dosage of chlorine or peroxide makes it easy to control.
  • After the peroxide injection system, use a  whole house carbon filter to remove any residual chlorine or peroxide residual in the water.
  • The result is clean, fresh, disinfected, odor-free, chlorine-free water throughout your home.
  • Safe for septic tank systems
  • Works over a wide range of water flow rates for most home water wells
  • Good for chlorinating well water flow rates from 1 to 50 Gallons Per Minute (1 – 50 GPM)
  • Works for line pressures up to 110 PSI
  • Unlike Stenner-style or other types of peristaltic pumps, good quality diaphragm pump has no pump tube failures, no rollers to go bad, need less frequent service, and are good for continuous duty

Hydrogen sulfide gas (“H2S”), has a distinctive “rotten egg” sulfur odor, which may be especially noticeable when running hot water.

Such water can discolor coffee, tea, and other beverages, and alter the appearance and taste of cooked foods. Hydrogen sulfide (“H2S”) gas is a nuisance that is not usually a health risk at concentrations normally found in household water.

Hydrogen sulfide can be toxic. Usually, the gas can be detected long before it reaches harmful concentrations. H2S is flammable and poisonous.

H2S dissolved in water can corrode plumbing metals, such as iron, steel, copper, and brass and exposed metal parts in washing machines and other water-using appliances.

The corrosion of iron and steel from hydrogen sulfide forms ferrous sulfide or “black water” which can darken silverware and discolor copper and brass utensils.

Hydrogen sulfide can also interfere with the effectiveness of water softeners and filter systems.

Sources of Hydrogen Sulfide

Iron bacteria and sulfur bacteria present in groundwater use iron and sulfur as an energy source and chemically change sulfates to produce H2S gas.

These bacteria use the sulfur available from decaying plants, rocks, or soil and often thrive in an iron-rich environment.

The harmless non-toxic bacteria normally exist in oxygen-deficient environments, such as deep wells and plumbing systems. The bacteria do not usually cause health problems but contribute to bad tastes and/or odors at low levels.

The harmless non-toxic bacteria normally exist in oxygen-deficient environments, such as deep wells and plumbing systems. The bacteria do not usually cause health problems but contribute to bad tastes and/or odors at low levels.

Hydrogen sulfide gas may also be present naturally in wells drilled in shale or sandstone, near coal or peat deposits, or oil fields.

Though H2S is normally found in wells, it can also enter surface water through springs and quickly escape into the atmosphere.

Often your water heater can become a source of foul H2S odors. The magnesium rod used in heaters for corrosion control can chemically reduce sulfates to hydrogen sulfide gas (rotten egg odor) and may need to be replaced with a different type of anode.

This odor can also be eliminated with the use of a Water Heater Odor Killer.

Sulfur Smell in Well Water Health Effects

High levels of sulfur odor (hydrogen sulfide gas) 100 PPM or over can cause sickness and death.  However, the levels found in homes or from well water is lower in the range of 1 – 5 PPM.

Low Concentration Immediate/Short Term Exposure :

  • Irritation of the eyes, nose, throat (watery eyes)
  • Irritation of the respiratory system (cough, shortness of breath) especially if you have asthma

Low Concentration Repeated/Prolonged Exposure :

  • Eye inflammation
  • Headache
  • Fatigue
  • Irritability
  • Insomnia
  • Weight loss with digestive disturbances 

Moderate Concentrations:

  • More severe eye irritation
  • Severe respiratory irritation (cough, difficulty breathing, accumulation of fluid in the lungs)
  • Headache and dizziness 
  • Nausea 
  • Vomiting
  • Staggering
  • Excitability 

High Concentration:

  • Shock
  • Convulsions
  • Inability to breathe
  • Extreme rapid unconsciousness 
  • Coma
  • Sometimes death

Information provided by OSHA

What is the Difference Between Sulfate and Hydrogen Sulfide?

Sulfate is a dissolved naturally occurring mineral and at levels of 250 PPM can cause a laxative effect if the water is consumed. High levels of sulfate can be easily tested with a test kit or laboratory analysis.

Hydrogen sulfide is gas and must be tested on-site. Sulfate has no odor, but high levels of sulfate with water that is not disinfected can cause hydrogen sulfide by the action of sulfate-reducing bacteria.


Do you have rotten egg or sulfur odors in your cold or hot water?  Or would you like more help in learning how to treat sulfur odors in well water?

Email our technical support department at [email protected] or call us for help!

Read More About How To Treat Sulfur Odor in Well Water

Read the PDF on Hydrogen Sulfide and Sulfate
Drinking-Water Wells produced by the University of Massachusetts

Water Heater Odors Only?

Read How to Eliminate Odors from Hot Water

How to Treat Sulfur Odors In Well Water Infographic:

How to treat sulfur odors in well water

  • Clean Water Systems & Stores, Inc., Water Treatment Equipment,Service & Supplies, Santa Cruz, CA

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