Why Does My Water Smell Like Rotten Eggs? (Sulfur Smell Explained)

A rotten egg odor coming from your water can be alarming. This smell typically occurs when naturally occurring sulfur-reducing bacteria (SRB) is active in the water.

The metabolic activity of these harmless bacteria causes hydrogen sulfide (H2S) gas, which is the most common cause of a sulfur smell in water. H2S is a poisonous gas when airborne and, while uncommon, can be dangerous to your health when concentrations in your water are high enough.

Your Hot Water Heater Could Be the Culprit

There are several ways hydrogen sulfide gets into your water supply, and depending on whether the water is hot or cold, the solution may be different. First, check the smell of water from your hot and cold faucets.

Does both hot and cold water have the rotten egg smell in water, or is the odor stronger from one tap than the other?

Why Does My Hot Water Smell Like Rotten Eggs?

If you notice a sulfur smell in hot water only, the issue may be caused by the presence of sulfur-reducing bacteria in the low-oxygen (anaerobic) environment of the water heater. In addition, the magnesium anode rod in tank water heaters can increase odor production through chemical reactions between it and the water.

As the anode rod corrodes, it reacts with the water and enhances the rotten egg smell. Replacing the anode rod with a different type and flushing the water heater often helps this situation. Contact a plumbing specialist if you need water heater repair and maintenance.

Why Does My Cold Water Smell Like Sulfur?

If there’s a rotten egg smell coming from your cold water, too, then the sulfur-reducing bacteria could be in the groundwater, plumbing system, water softener or private well. A sulfur smell in well water is especially common in areas with naturally occurring sulfur compounds underground.

Pollution of your municipal water source is another possible cause of the smell. There are many sources of drinking water contamination, from runoff into rivers to naturally occurring contaminants that basic water treatment systems often don’t fully remove.

Common Sources of Sulfur Smell in Water

To properly specify water treatment equipment for hydrogen sulfide issues, it is best to understand the possible sources of contamination.

Sulfur-Reducing Bacteria

Sulfur is a naturally occurring element commonly in the form of sulfate in groundwater. It can also be found as an industrial or mining byproduct. As sulfur bacteria in water break down these compounds, sulfate is converted into sulfide gas, creating the characteristic rotten egg odor. Whether you have city or well water, hydrogen sulfide in drinking water can become an issue for homeowners.

Natural Geological Sources

Certain types of bedrock, including shale and sandstone, naturally can contain sulfates. Volcanic and hydrothermal regions may also contain elevated levels of hydrogen sulfide gas that can enter groundwater supplies.

Chemical reactions inside water heaters — particularly involving the magnesium anode rods — can intensify rotten egg odors in household water.

Plumbing System Corrosion

As pipes in your home age, they can begin to break down and corrode. This process causes a chemical reaction between the metal of the pipes and the water which creates hydrogen sulfide. Corroding pipes are also more susceptible to bacteria growth, in turn making your water smell or taste like rotten eggs.

Sewage or Environmental Contamination (Rare)

While unlikely, pollution and sewage issues may be causing the rotten egg smell in your water. It’s important to get your water tested for E. coli and other contaminants harmful to your health and home.

Is Water That Smells Like Rotten Eggs Safe to Drink?

Small amounts of hydrogen sulfide in drinking water are not typically considered a health risk, though they can make water taste and smell unpleasant. High concentrations of sulfate in the water can lead to gastrointestinal issues for some people. The EPA’s secondary limit for sulfates is 250 mg/L in drinking water.

Drinking water purification by reverse osmosis can reduce sulfates in drinking water — up to 98% with a Kinetico RO system. If you notice a persistent sulfur smell in water from your tap, it is best to have your water tested by a water quality professional.

Health Effects of Sulfur in Drinking Water

Drinking water with sulfur in it may cause diarrhea, cramps, dehydration and gastrointestinal irritation in some individuals. Babies and people with sensitive stomachs may be especially susceptible to these symptoms. Also, showering or bathing in sulfuric water increases bacteria growth on skin and subsequent inflammation and irritation.

Sulfuric water impacts your home with potentially expensive side effects. Sulfur bacteria and the additional bacterial growth it causes produce a slime that can build up and clog your plumbing, well and even irrigation systems.

Over time, hydrogen sulfide and bacteria can corrode pipes, damage appliances and leave plumbing fixtures or silverware stained gray, black or reddish-brown — all costly side effects of poor water quality.

• Gastrointestinal issues: Sulfur acts as a mild laxative and can trigger diarrhea, nausea and gastrointestinal discomfort, especially for infants and people with sensitive stomachs.
• Dehydration risk: If you suffer from diarrhea as a result of drinking sulfur-rich water, this can dehydrate you due to fluid loss.
• Taste and odor: The unpleasant smell of rotten eggs in your water can be off-putting , whether cooking, drinking or even brushing your teeth.
• Typically no major health risks: Sulfuric water poses no known long-term serious impacts on your health. While rare, the source of sulfur bacteria could be sewage leaching into your water supply, which can pose more serious risks. Get your water tested if you are unsure and to help address the root cause.

How Do I Treat Sulfuric Water?

The most effective way to remove the sulfur smell from water will depend on the source of the issue and the concentration of hydrogen sulfide present.

Professional water testing provides a reliable first step to identifying where the odor is coming from so the right treatment solution can be recommended.

Reverse Osmosis Systems

Get rid of unwanted sulfur smells and hydrogen sulfide in your water with a reverse osmosis purification system. Reverse osmosis can filter almost all contaminants found in water, including sulfur bacteria, minerals, metals, pharmaceuticals and PFAS forever chemicals.

Whole-Home Sulfur Filtration

For persistent hydrogen sulfide odors, a specialized whole-home filtration system can help reduce these odors throughout the home. The Kinetico Sulfur Guard™ backwashing filtration systems are specifically designed to treat rotten egg odors in well water systems.

Water Heater Maintenance

It’s recommended to schedule yearly maintenance for your hot water heater to flush the system, prevent corrosion and extend its lifespan.

Water heater maintenance and the installation of a whole-home water system both help protect the efficiency of your appliances long-term from sulfur bacteria, from your washing machine to the dishwasher and garbage disposal.

Improve Your Health With Kinetico Advanced Water Systems

Kinetico Advanced Water Systems specializes in helping homeowners get rid of odd water smells and impurities, for better tasting and healthier water for your whole family.

Looking to stop water contamination at the source? Investing in a whole-home water filtration or purification system helps remove sulfur bacteria and other contaminants before they even make it to your tap and water heater.

Schedule your free water analysis today to get a complete understanding of your water and find the best solution for your home.