How to Eliminate Rotten Egg Smell (Sulfur) in Your Water

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By Eric Phillips

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Are you tired of dealing with the foul odor of rotten eggs in your water? Whether you're washing dishes, doing laundry, or taking a shower, that unpleasant smell can be a constant annoyance. But fret not!

If your water has elevated sulfur levels, the best method for treating it is with a whole house well water filtration system. There are three main treatment options available:

  1. Air Injection Oxidation
  2. Hydrogen Peroxide Injection
  3. Activated Carbon Filtering

Before deciding on a treatment option, it's essential to determine the source of the rotten egg smell.

How to Find the Source of Rotten Eggs Smell in Water

To find the source of the rotten eggs smells in water, follow these steps:

  1. Check all faucets: The rotten egg smell may be present in all faucets, or it may only be present in certain ones. This can help you narrow down the source of the odor.
  2. Check the hot water: Run the hot water faucet separately for several minutes and observe if the rotten egg smell is stronger. If it’s, the odor is likely coming from your water heater.
  3. Check the cold water: Fill a 5-gallon bucket with water from as close to your well as possible. If the water in the bucket has a rotten egg odor, it suggests a problem within your well or groundwater.
  4. Check the water softener: If the cold water from your private well is odorless, but the cold water passing through a water softener has a rotten egg smell, it indicates the presence of sulfur bacteria in the water softener.

How to Remove Sulfur from the Well and/or Plumbing System

The average sulfur concentration in most wells in the United States is 1-5 ppm (parts per million), according to The National Ground Water Association (NGWA). However, in some cases, sulfur levels can reach 30-50 ppm, and in very rare cases, concentrations of 100 ppm may occur.

Best Removal MethodSulfur in WaterOther Contaminants
Air Injection Oxidation (AIO). Recommended Product: Springwell's Air Injection Oxidation FilterRemoves up to 8 ppm (mg/l)Removes iron up to 7 ppm, manganese up to 1 ppm
Injection of Hydrogen Peroxide (H2O2). Recommended Product: Matrixx inFusion SystemRemoves up to 30 ppm (mg/l)Removes iron up to 20 ppm, manganese up to 1 ppm
Activated Carbon FilteringRemoves up to 5 ppm (mg/l)Removes iron up to 10 ppm, manganese up to 1 ppm

1. Air Injection Oxidation (AIO)

Air injection oxidation (AIO) is a water treatment method that can be used to remove sulfur from water. It works by injecting air into the water, which helps to oxidize the sulfur and remove it from the water.

When air is injected into water, it creates tiny bubbles. These bubbles come into contact with the sulfur in the water, and the oxygen in the air reacts with the sulfur to form sulfates. Sulfates are less soluble in water than hydrogen sulfide, so they are more easily removed from the water.

AIO filtration system doesn't require the use of chemicals and is relatively easy to install and maintain. However, it can be expensive and requires regular backwashing.

As the filter media captures precipitated hydrogen sulfide and other contaminants like iron and manganese, it can become clogged over time. Regular backwashing is necessary to clear the filter media and maintain optimal performance.

The AIO filtration method can remove up to 10 ppm of hydrogen sulfide from the water. However, the actual amount of sulfur that is removed will depend on the level of sulfur in the water and the type of filter media that is used.

For instance, some whole-house iron filters, like Springwell's Air Injection Oxidation Filter, can remove up to 8 ppm of hydrogen sulfide, along with up to 7 ppm of iron and 1 ppm of manganese.

2. Hydrogen Peroxide Injection

Hydrogen peroxide is a disinfectant that can be used to remove sulfur from water. It works by oxidizing the hydrogen sulfide and sulfates in the water, which renders the water free from sulfur and other heavy metals like iron and manganese. This mechanism ensures the removal of unpleasant odors and improves the water quality.

When hydrogen peroxide is injected into water, it reacts with the sulfur to form sulfates. Sulfates are less soluble in water than hydrogen sulfide, so they are more easily removed from the water. The hydrogen peroxide also oxidizes iron and manganese, which cause reddish-brown or black staining in sinks, tubs, and laundry.

Hydrogen peroxide injection can remove up to 30 ppm of sulfur from water. This is the maximum amount of sulfur that can be removed with this method, and the actual amount of sulfur that is removed will depend on the level of sulfur in the water and the amount of hydrogen peroxide that is injected.

For example, if the level of sulfur in the water is 20 ppm, then hydrogen peroxide injection can remove up to 20 ppm of sulfur, leaving 0 ppm of sulfur in the water. However, if the level of sulfur in the water is 50 ppm, then hydrogen peroxide injection can only remove 30 ppm of sulfur, leaving 20 ppm of sulfur in the water.

A hydrogen peroxide injector system can be installed at the wellhead or at the point of entry into your home. The system typically consists of a pump, a tank of hydrogen peroxide, and a controller. The pump will inject the hydrogen peroxide into the water, and the controller will ensure that the correct amount of hydrogen peroxide is injected.

The hydrogen peroxide injector system will need to be maintained regularly. This includes inspecting the system for leaks, replacing the tank of hydrogen peroxide as needed, and conducting a catalytic carbon backwash to remove residual hydrogen sulfide and heavy metals from the water.

A catalytic carbon backwash is a process that can be used to remove residual hydrogen sulfide and heavy metals from water. The backwash consists of passing the water through a bed of activated carbon, which removes the residual contaminants.

3. Activated Carbon Filtering

Activated carbon filters are a type of water filter that can be used to remove sulfur from water. Activated carbon is a porous material that has a large surface area, which allows it to absorb a variety of contaminants, including sulfur.

When water passes through an activated carbon filter, the sulfur molecules attach to the surface of the carbon. The sulfur molecules are then trapped in the carbon, and the water flows out of the filter free of sulfur.

Activated carbon filters are effective in removing up to 5 ppm of sulfur from water. If the concentration of sulfur in your water is high, you may need to use a different method of sulfur removal, such as air injection or chlorination.

Activated carbon filters also remove other organic contaminants from water and improve the taste and odor of water. They are relatively easy to install and maintain but can be expensive and require regular replacement of filter cartridges.

How to Remove Sulfur Bacteria from Well Water

Shock chlorination is a method of treating well water that uses a strong dose of chlorine to kill bacteria and other microorganisms. It's a common method for removing sulfur bacteria from wells that causes a rotten egg odor.

Chlorine is a powerful oxidizing agent that kills sulfur bacteria by destroying their cell walls. When chlorine is added to well water, it reacts with the sulfur bacteria and other microorganisms, killing them.

To perform shock chlorination, you will need to add a measured amount of chlorine bleach to your well water. The amount of chlorine bleach that you need to add will depend on the size of your well and the level of sulfur bacteria in the water. A general rule of thumb is to add 200 ppm of chlorine for every 1,000 gallons of water in your well.

You will need to mix the chlorine bleach with water to create a solution. The ratio of chlorine bleach to water should be 1:10. For example, if you need to add 1 gallon of chlorine bleach, you will need to mix it with 10 gallons of water.

After you have added chlorine bleach to your well water, you will need to let the water sit for at least 24 hours. This will allow the chlorine to kill the sulfur bacteria and other microorganisms in the water.

After the shock chlorination is completed, it's important to test the water to make sure that the sulfur bacteria have been killed. You can test the water for chlorine residual using a test kit.

In some cases, shock chlorination may not be enough to remove all of the sulfur bacteria from your well. In these cases, It’s recommended to enhance the purification process with another treatment, such as air injection oxidation or hydrogen peroxide treatment.

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How to Remove Rotten Eggs Smell from the Water Heater

To remove the rotten egg smell from your water heater, you can follow these methods based on the specific cause of the odor:

  • Replace the sacrificial anode rod: If the rotten egg smell is caused by the corrosion of the magnesium or aluminum anode rod, you can replace it with a durable rod.
  • Disinfect the water heater with chlorine bleach: If the anode rod isn’t corroded, sulfate-reducing bacteria are responsible for the odor. Chlorine bleach can be used to disinfect the water heater and kill the bacteria.

How to Replace the Sacrificial Anode Rod from Water Heater

Generally, a magnesium or aluminum anode rod typically lasts 3 to 5 years in a water heater, but it can corrode more quickly in areas with high levels of sulfur or hard water.

To prevent the rotten egg smell and extend the life of your water heater, you can replace the sacrificial anode rod with a CorroProtec-powered anode rod. This anode rod is made of titanium with a mixed metal oxide coating, which resists corrosion and prevents hydrogen sulfide gas release.

The CorroProtec-powered anode rod is backed by a 20-year warranty, so you can be confident that it will last for many years to come. If it fails within the warranty period, the company will provide a free replacement.

It's important to note that removing the anode rod entirely isn't a viable solution. This can significantly speed up the corrosion of the water heater's inner lining, thereby reducing its lifespan. Instead, always opt for replacing the sacrificial rod with a durable alternative.

To replace the sacrificial anode rod in your water heater, you will need the following tools and materials:

  • CorroProtec-powered anode rod
  • Socket wrench
  • 1 1/16 inch socket
  • 24-inch cheater bar
  • Flat blade screwdriver
  • Teflon tape
  • Garden hose

Follow these steps to replace the sacrificial anode rod:

  1. Turn off the power supply (gas or electric) to the water heater and close the shut-off valve at the cold water inlet line.
  2. Open a hot water faucet in the house to release the pressure inside the water heater's tank.
  3. Attach a garden hose to the drain valve at the bottom of the water heater and drain approximately two to three gallons of water from the tank.
  4. Locate the anode rod position at the top of the water heater. If it's not visible, use a screwdriver to expose the anode rod head by removing the insulation.
  5. Use a 1 1/16 inch socket and a cheater bar for leverage to apply greater force to turn the anode rod counterclockwise and remove it.
  6. Carefully lift the anode rod out of the tank. Be cautious as it may be hot. If it’s deteriorated, it indicates it has been doing its job.
  7. Wrap Teflon tape (six or more turns) around the threads of the new CorroProtec-powered anode rod.
  8. Insert and tighten the CorroProtec-powered anode rod securely in place.
  9. Open a hot water faucet in the house, then turn on the cold water supply to the heater and let the tank fill. After a minute or two, turn off the hot water faucet.
  10. Check for leaks around the CorroProtec-powered anode rod. If there are no leaks, replace the plastic cap on top.
  11. Finally, turn the power supply (electric or gas) back on.

Make sure to follow the manufacturer's guidelines specific to your water heater model during the replacement process. If you're uncertain or uncomfortable with the replacement procedure, it's recommended to seek assistance from a plumber or handyman to ensure proper installation.

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How to Disinfect Water Heater With Chlorine Bleach

Chlorine bleach can be used to disinfect water heaters and kill sulfur bacteria. Here are the materials you will need:

  • Neutra Sul or a similar commercial-grade hydrogen peroxide solution.
  • Water
  • Measuring cup
  • Bucket
  • Protective gloves and eyewear
  • Mask or cloth

Follow these steps to disinfect and flush the water heater using chlorine bleach:

  1. Wear protective gloves and safety goggles, and a mask or cloth to cover your mouth and nose.
  2. Turn off the water supply by closing the cold water inlet and power or fuel supply (electric or gas) to the water heater. Turning off the power source or fuel supply is important to prevent the heating element or burner from activating while the bleach is in the tank.
  3. Drain at least 3 to 4 gallons of water from the drain valve on the water heater. Be cautious as water could be hot.
  4. Prepare a hydrogen peroxide solution to disinfect the water heater. For a standard 40-gallon water heater, mix ½ gallon (8 cups) of Neutra Sul bleach with 4 gallons of water in a bucket. Adjust the amounts proportionally for larger or smaller water heaters. Use a measuring cup or container to accurately measure the bleach.
  5. Carefully pour the hydrogen peroxide solution into the water heater through the hot water outlet opening. Be cautious not to spill any bleach on the surrounding areas.
  6. Re-connect the hot water supply line to the hot water outlet on the water heater.
  7. Turn on the water supply and draw water at each hot water faucet in the house until you notice a chlorine smell in the water. This helps to distribute the bleach throughout the tank and the water supply line.
  8. Once you notice a chlorine smell, turn off all the hot water faucets and allow the bleach to sit in the water heater and water supply lines for at least 3 hours. During this time, the bleach will disinfect the tank and kill the sulfur bacteria.
  9. After the waiting period, open a hot water faucet in your home to release any trapped air and allow the water to flow. Let the hot water run for several minutes until you no longer smell the chlorine odor. This indicates that the tank is properly flushed.
  10. Close the hot water faucet and restore the gas or electricity supply to the water heater as per the manufacturer's instructions.
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How to Eliminate Sulfur-Bacteria from Water Heater by Heating

To eliminate the rotten egg smell caused by sulfate-reducing bacteria in your water heater, raise the water temperature by following these steps:

  1. Check the manufacturer's guidelines. Some water heaters have a maximum temperature of 140°F, so it is important to check your specific model before proceeding.
  2. Increase the water temperature to the maximum recommended level, typically around 160°F. This elevated temperature will help kill the sulfur bacteria.
  3. Maintain the temperature at 160°F for a duration of three hours. This extended period will ensure the complete elimination of the sulfur bacteria.
  4. After the three-hour heating period, flush the water heater tank to remove any dead bacteria and sediment.
  5. Once the bacteria elimination process is complete, remember to adjust the thermostat back to a safe and comfortable temperature to prevent scalding hot water during future use.

It's important not to exceed the manufacturer's recommended temperature, as doing so may risk damaging your water heater.

Why Does Water Heater Smell Like Rotten Eggs?

The water heater smells like rotten eggs due to hydrogen sulfide gas (H2S) that originates from the corrosion of the anode rod or the activity of sulfate-reducing bacteria (SRB).

In a water heater, the anode rod, typically made of magnesium or aluminum is a sacrificial metal that is designed to draw corrosive minerals away from the inner lining of the hot water tank, protecting it from corrosion. When the anode rod corrodes, it reacts with sulfates in the water, producing hydrogen sulfide gas.

In addition to the anode rod, sulfate-reducing bacteria (SRB) can also produce hydrogen sulfide gas. SRB are bacteria that thrive in warm, oxygen-depleted environments, such as the inside of a water heater. When SRB interact with sulfate-containing minerals in water, they produce hydrogen sulfide gas as a byproduct.

The combination of hydrogen sulfide gas from the anode rod and SRB bacteria causes a strong rotten egg odor within the water heater.

How to Remove Rotten Eggs Smell from the Water Softener

To remove sulfur odor from your water softener, gather the following materials:

  • Res Care Liquid (resin bed cleaner)
  • Neutral Sul or a similar commercial-grade hydrogen peroxide solution
  • A measuring cup
  • Rubber gloves or protective eyewear (optional)

Follow these steps to remove the rotten egg smell from the water softener:

  1. Disconnect the power supply and shut off the water inlet valve to the water softener.
  2. Clean the resin tank using a Res Care Liquid to remove contaminants and buildup.
  3. If desired, wear rubber gloves and protective goggles to handle the hydrogen peroxide solution.
  4. Prepare a hydrogen peroxide solution by mixing 1 gallon of Neutral Sul with 4 gallons of water for a 40-gallon water softener. For an 80-gallon water softener, use 2 gallons of hydrogen peroxide with 8 gallons of water.
  5. Pour the hydrogen peroxide solution into the brine tank (salt storage tank) of the water softener.
  6. Initiate a manual regeneration cycle on the water softener according to the manufacturer's instructions.
  7. Allow the hydrogen peroxide solution to sit in the water softener system for at least 2 hours to disinfect and eliminate sulfur bacteria causing the odor.
  8. Run several regeneration cycles or flush the system to remove the hydrogen peroxide solution and any remaining bacteria.
  9. Recharge the system with clean, high-quality salt following the manufacturer's recommendations.
YouTube video

How to Test for Sulfur in Water

If your water has a rotten egg odor, it likely contains hydrogen sulfide. There are two common methods for testing for sulfur in water:

  1. Lead acetate test strips: This is a quick and inexpensive test that can be done at home. Simply dip the strip in your water and wait for the color to change. Compare the color of the test strip to the color chart. The color chart will indicate whether or not there is sulfur in the water. The downside of the lead acetate test strip method is that it doesn't provide any information about the concentration of sulfur in the water.
  2. Laboratory analysis: This is the most accurate way to test for sulfur in water. If you draw water from a private well, it’s recommended to conduct comprehensive testing for various contaminants in addition to sulfur. You can order a water test kit from a laboratory like SpringWell ETR laboratories. Collect a minimum of 100 milliliters (3.4 ounces) of well water, follow the instructions provided, and mail the sample to the laboratory for analysis. Within 1 to 3 business days, the laboratory will provide a detailed report, including the analysis of 53 different contaminants, including sulfur, in your well water.

Sulfur in well water can sometimes indicate contamination from local sewage, but it can also be naturally occurring. The Centers for Disease Control and Prevention (CDC) recommends testing once a year for total coliform bacteria, nitrates, total dissolved solids, and pH levels in well water. However, the CDC now also recommends testing for arsenic, radon, and lead, as these contaminants can have serious health effects.

Depending on the specific levels of sulfur in your water, you can select the appropriate well water filtration system for sulfur and other well water contaminants such as iron and manganese. However, if the well water is contaminated with sulfur bacteria, it must be treated with chlorination.

What is Hydrogen Sulfide?

Hydrogen sulfide (H2S) is a colorless, flammable, and poisonous gas with a pungent odor similar to rotten eggs. This gas is the main cause of the unpleasant smell in water, particularly well water. When water contains hydrogen sulfide, its foul odor makes it unpleasant for drinking, cooking, or other household tasks such as washing, cleaning, and showering.

Hydrogen sulfide is commonly found in groundwater due to reactions with sulfur-containing minerals in soil and rocks. It can also come from sulfur-reducing bacteria in wells, plumbing, or water heaters, which produce hydrogen sulfide. In rare cases, hydrogen sulfide can result from sewage or pollution contaminating the water supply.

What are the Risks of Having Hydrogen Sulfide in Water

There are several risks of having hydrogen sulfide in the water. These include:

  • Health effects: The impact of hydrogen sulfide on our health can vary depending on its concentration in the water. When ingesting water with 1 ppm of hydrogen sulfide, it can cause digestive issues like nausea, vomiting, and diarrhea. At higher concentrations, around 10 ppm, it can lead to respiratory problems such as coughing, shortness of breath, and difficulty breathing. In more severe cases, at a concentration of 100 ppm, it may cause neurological problems like headaches, dizziness, and confusion.
  • Staining and discoloration: At concentrations as low as 0.01 ppm, the presence of hydrogen sulfide, along with iron and manganese, in water can result in black or gray stains on plumbing fixtures, washing machines, kitchenware and surfaces. These stains can be difficult to remove and may leave a greasy feeling. When chlorine bleach is used in laundry, it can react with iron and manganese, leading to dark rusty or brownish stains on clothes.
  • Damage to plumbing and appliances: In concentrations as low as 10 ppm, hydrogen sulfide exhibits corrosive properties, potentially leading to damage to your plumbing systems, including pipes, fixtures, and water-using appliances such as water heaters, dishwashers, and washing machines. This corrosion can result in leaks, damage, and the requirement for repairs or replacements.
  • Corrosion and discoloration of metals: In concentrations as low as 1 ppm, hydrogen sulfide can corrode metals such as iron, silver, copper, and brass. This corrosion of metals due to hydrogen sulfide causes the blackening of silverware and the discoloration of copper and brass utensils.
  • Reduces cleaning power of detergents: Even at concentrations as low as 0.5 ppm, hydrogen sulfide in water reduces the effectiveness of detergents like laundry and dishwashing detergents. Sulfide ions react with the active ingredients of detergents, hindering their ability to break down grease, oils, and stains. This leads to less effective cleaning, leaving clothes and dishes inadequately cleaned with persistent greasy or stained residue.

It’s important to note that hydrogen sulfide in water isn't regulated by the U.S. Environmental Protection Agency (EPA). The risks associated with hydrogen sulfide are primarily related to high air concentrations rather than water.

The World Health Organization (WHO) recommends that the concentration of hydrogen sulfide in air should not exceed 0.005 ppm. The Occupational Safety and Health Administration (OSHA) states that hydrogen sulfide can cause irritation to the eyes, throat, and respiratory system at concentrations below 20 ppm. Pain in the eyes can occur at around 6.5 ppm, while breathing can be impacted at approximately 2 ppm.

Conclusion

Rotten egg smells in water can be unpleasant and uninviting. They can originate from various sources such as a well, water heater, or water softener. The sulfur smell in water is caused by hydrogen sulfide, a gas naturally present in some groundwater or produced by bacteria reacting with sulfur-containing minerals.

To eliminate the rotten egg smell in water, identify the source and treat it using solutions like air injection oxidation or hydrogen peroxide. These treatments effectively remove sulfur as well as iron, and manganese, providing clean, odorless, and fresh-tasting water for your off-grid living needs.

Eric Phillips

Meet Eric, the Water Treatment Specialist and founder of Dripfina, where he shares his wealth of expertise. With notable features in Realtor, ApartmentTherapy, FamilyHandyMan, and more, Eric is a renowned expert in water treatment industry. Join Eric on Dripfina and benefit from #AskDripfina community to make informed decisions for clean, refreshing water.

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