A glass of water should be refreshing. It should taste crisp and clear and it definitely shouldn’t have any offputting odors. But when your water smells like rotten eggs, you know something is wrong.
Whether you’re drawing your water from a private well or you’re on the city grid, a rotten egg smell is nothing to sniff at. Fortunately, you don’t have to suffer the smell forever – you can remove it.
Let’s find out why your water smells like rotten eggs, and how to get rid of the smell.
Rotten Egg Smell in Water – What's Causing It?
Hydrogen sulfide gas (H2S) is the cause of water smelling like rotten eggs. It occurs naturally in groundwater as a result of chemical reactions in the soil. Sulfur bacteria living in well water or plumbing can also cause hydrogen sulfide. Chemical reactions in water heaters can also produce hydrogen sulfide. In rare cases, hydrogen sulfide can also be a result of sewage or pollution contaminating the water supply.
Water Heater Smelling Like Rotten Eggs? Here's Why
When the anode rod in your water heater corrodes, it reacts with sulfates in the water to create hydrogen sulfide gas. This gas is responsible for the rotten egg smell in the water. Additionally, the warm environment of the water heater can provide a habitat for sulfur bacteria to thrive.
Anode rods are designed to corrode in order to protect the inner lining of the hot water tank from corrosion. These rods are made from magnesium or aluminum and are intended to attract corrosive minerals away from the tank. However, when sulfates are present in the water, they react with the corrosion of the anode rod to create hydrogen sulfide gas.
If the sulfur odor is only present in hot water, it's likely caused by contamination within the water heater. It's recommended to replace the anode rod every 3-5 years, but if you notice a rotten egg smell, it should be replaced sooner.
Hydrogen Sulfide in Drinking Water – The Problems
Hydrogen sulfide in drinking water can produce an unpleasant rotten egg smell, but it's not typically a health concern. The Environmental Protection Agency doesn't regulate hydrogen sulfide levels in drinking water. The main dangers of hydrogen sulfide come from high concentrations in the air, rather than in drinking water.
Moderate concentrations of hydrogen sulfide can be corrosive and damage plumbing and household appliances. High concentrations in the air pose a serious risk to health. The World Health Organization recommends that hydrogen sulfide concentrations shouldn't exceed 0.005 PPM in the air.
Health Risks of Hydrogen Sulfide
According to the Occupational Safety and Health Administration (OSHA), low concentrations of hydrogen sulfide in the air can cause irritation to the eyes, throat, and respiratory system. Repeated exposure increases the risk and studies have shown that pain in the eyes can occur at 6.5 PPM in the air and breathing can be impacted at 2 PPM. (1)
High concentrations of over 100 PPM pose an immediate danger to health and life, but these concentrations are rare outside of industrial settings and not present in drinking water. At 150 PPM, hydrogen sulfide can cause a loss of sense of smell for most people. The Environmental Protection Agency (EPA) research has found no link between hydrogen sulfide gas and cancer. (2, 3)
Damage to Your Pipes and Plumbing
Hydrogen sulfide can cause damage to pipes and appliances in concentrations of 1 PPM. This includes corrosion to copper pipes and silverware.
Encouraging Bacterial Growth
Sulfur bacteria produce a slime that houses other bacteria, such as iron bacteria. This slime can also clog wells and plumbing, causing damage.
What to Do When Your Water Smells Like Rotten Eggs?
If your water smells like rotten eggs, you need to determine the source of the odor. Is the smell present in cold water only or does it also occur when the water is heated? Once you know the source, you can identify the cause and find a solution.
Step 1: Check for The Source of the Smell
First, test both your cold and hot water. To test your cold water, fill a 5-gallon bucket from a source close to your well. If the water smells like rotten eggs, the issue is within your well or groundwater. If cold water from your well or the city grid doesn't smell like sulfur, but your cold water does after passing through a water softener, the issue is likely sulfur bacteria in your water softener.
If your cold water doesn't have a rotten egg smell, check your hot water. If the sulfur smell only comes from hot water, the issue is with your water heater.
Step 2: Test for Hydrogen Sulfide
Test for Hydrogen Sulfide in your water using lead acetate test strips. Simply submerge the strip in your water and observe any color change to identify the presence of hydrogen sulfide. Alternatively, if your water smells like rotten eggs, it's likely that hydrogen sulfide is present.
If you're drawing water from a private well, it's recommended to test for a wide range of contaminants. Consider consulting with a professional from your local water quality experts or county government to guide you to licensed laboratories.
Note that while hydrogen sulfide usually only affects the taste and smell of your drinking water, it may indicate contamination from local sewage. It's recommended to conduct an annual test for coliform bacteria like E. coli as advised by the Center For Disease Control (CDC).
How to Remove Sulfur Odor from Your Water Heater
To fix a sulfur odor in your water heater, consider the source of the odor. If it's from chemical reactions in the heater, replace the anode rod to stop corrosion and the creation of hydrogen sulfide. If the odor is from sulfur bacteria in well water, disinfect the heater with chlorine.
Replace or Remove Anode
The anode rod in your water heater is made from magnesium or aluminum. As it corrodes, it produces hydrogen sulfide, which can cause a sulfur smell in your water. These rods are designed to be replaced and can be accessed through a plug at the top of the water heater.
Removing the rod entirely may stop the sulfur smell in your water, but it can also dramatically reduce the lifespan of your hot water heater. The inner lining of the heater will corrode faster without the anode rod. To avoid this, it's better to replace the rod with an aluminum alternative.
To replace your anode rod, turn off the water and release the pressure from your heater. Unscrew the plug to remove the rod and replace it with a new one. Always check the manufacturer's guidelines for your water heater before undertaking a replacement, or call in a professional.
Disinfect with Chlorine Bleach
To eliminate sulfur bacteria causing a rotten egg smell in your water heater, try chlorination. Disinfect and flush the heater using one gallon of chlorine bleach.
Kill Sulfur Bacteria by Heating Water
To eliminate sulfur bacteria and the rotten egg smell, heat your water to a temperature of 160 degrees Fahrenheit. Sulfur bacteria die at this temperature. (4) Set your water heater to 160°F and maintain this temperature for three hours to ensure the bacteria are killed. After the treatment, flush the tank to remove any dead bacteria.
However, it's important to note that many water heaters have a maximum temperature of 140°F. Going above this limit could damage your heater. Before proceeding, check the manufacturer's guidelines to ensure your water heater can handle the higher temperature. Once the treatment is finished, turn the thermostat down to prevent scalding hot water during future use.
How to Get Rid of Sulfur Smell in Well Water
The best way to remove sulfur odor from well water is by using a whole-house well water filter with an air injection oxidizing filter. Alternatively, shock chlorination or continuous injection of peroxide or chlorine can also effectively kill sulfur bacteria that produce hydrogen sulfide in a well.
Air Injection Oxidation (AIO)
Air Injection Oxidization (AIO) is an effective method for eliminating the rotten egg smell from water. It's a chemical-free process that injects air containing oxygen into the water supply to oxidize dissolved hydrogen sulfide. This turns the hydrogen sulfide into a form that can be captured by filter media.
AIO can remove large amounts of hydrogen sulfide, such as up to 8 PPM with Springwell's Whole-House Filter. However, regular backwashing is necessary to clear the filter media of accumulated precipitate hydrogen sulfide and other contaminants like iron.
Shock Chlorination with Chlorine Bleach
Shock chlorination kills sulfur bacteria in your well by disinfecting everything from the well depths to pumps and pipes. Use a strong dose of chlorine, around 200 PPM, for effective results. If your well has an exceptionally strong sulfur odor, this method is recommended. An air injection oxidization filter can also remove any residual hydrogen sulfide from your water supply.
Inject Chlorine or Peroxide Continuously
To disinfect water as it runs from your well, install a chlorine or peroxide injector system at the wellhead. This method is an alternative to shock chlorination. Chlorine effectively disrupts hydrogen sulfide on a cellular level, making it inactive. A catalytic carbon backwash can then be used to remove the chlorine, resulting in clean, odorless drinking water.
Activated Carbon Filtering
Activated carbon is a popular filter media for removing organic chemicals from drinking water. It can also remove hydrogen sulfide in small concentrations from your water supply, eliminating the rotten egg smell. (5)
However, if your water has a high level of hydrogen sulfide, air injection and chlorination are more effective solutions. But, if the smell of rotten eggs is mild and you're concerned about other organic contaminants, an activated carbon filter alone can work well.
Sewage Contamination
The rotten egg smell in your water may indicate hydrogen sulfide produced by sulfur bacteria, but it could also indicate sewage or pollution contamination in your water supply, particularly if your septic tank is located near your well.
To confirm the source of the smell, test your water for nitrate and coliform bacteria. If sewage contamination is present, the CDC advises drinking bottled water until a professional evaluate your well.
Final Thought
Rotten egg smells can be unpleasant and uninviting in a home. The smell of hydrogen sulfide is not refreshing and can originate from various sources such as a well, water softener, or heater.
However, finding the source and implementing solutions, such as a whole-house water filter for private wells, can effectively remove contaminants like sulfur, iron, and total dissolved solids (TDS) to ensure pure and purified water for off-grid living.
