Why Does My Water Smell Like Rotten Eggs?

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 dominant cause of rotten egg odor. H2S is a poisonous gas when airborne and, while uncommon, can be dangerous to your health when concentrations in your water are high enough.

How Does Sulfur Get in Your Water in the First Place?

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. Do both have the rotten egg odor or is one tap’s smell more noticeable than the other?

Sulfur is a naturally occurring element normally in the form of sulfate in groundwater. It can also be found as an industrial or mining byproduct. SRB activity reduces the sulfate to sulfide, generating the odors. Whether you have city or well water, hydrogen sulfide gas can be an issue for homeowners’ water.

Hot Water Rotten Egg Smell

If you smell sulfur only when the hot water is on, then it can be caused by the presence of sulfur-reducing bacteria in the anaerobic environment of the water heater. In addition, the magnesium anode rod in tank water heaters enhances odor production due to chemical reactions between it and the water.

As the anode rod corrodes it reacts with the water and enhances the rotten egg odor production. 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.

Cold Water Rotten Egg Smell

If there’s a smell of rotten eggs coming from your cold water, too, then the sulfur reducing bacteria could be in the groundwater, well, plumbing system or water softener. Pollution of your municipal water source is another possible cause of the smell. There are many sources of drinking water pollution, from runoff into rivers to naturally occurring contaminants, which often aren’t filtered by basic water treatment.

Conditions for Hydrogen Sulfide Production

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

• Bacteria: Hydrogen sulfide gas is produced when sulfur-reducing bacteria feed on sulfur-containing compounds in the water under low-oxygen conditions.
• Geological sources: Certain types of bedrock, like shales or sandstones, can contain sulfates. In addition, volcanic areas or hydrothermal areas are regions where H2S is prevalent and can get into the groundwater. 
• Chemical reactions: Water heater anode rods can drive chemical reactions in the water heater that enhance rotten egg odors.
• Sewage and other pollution: 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.

Corroding Pipes

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.

Is Water Containing Sulfates and Sulfides Safe to Drink?

Small amounts of hydrogen sulfide in your drinking water is not a health risk, but may make the water taste badly. 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. It is best to have your water tested by a water quality professional if you notice a persistent rotten egg odor coming from your tap.

Health Impacts of Sulfur in Water

Drinking water with sulfur in it may cause diarrhea, cramps and dehydration, as well as gastrointestinal irritation. Babies and people with sensitive stomachs will particularly experience these symptoms. 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; this can clog your plumbing, well and even irrigation systems. Over time, the presence of bacteria and hydrogen sulfide corrodes pipes, damages appliances and may leave your plumbing fixtures and kitchen 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?

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

For chronic hydrogen sulfur odors, a dedicated specialized filtration system can help reduce these odors throughout the home. The Kinetico Sulfur-Guard backwashing filtration systems are specifically designed to handle rotten egg odors in well systems.

It’s also 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 purification system removes 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 treatment solution for your home.