FIND A LOCATION NEAR ME 
Edit Location or Service
Sulfur Smell in Water: Where Does It Come From?
Turn Your Well Water Into Swell Water with Culligan Water
Read More
Take the next step
Additional Support
What to Expect at Your Culligan Water Test and Consultation
Discover More
Updated: February 24, 2023 August 12, 2021
While some water quality issues are imperceptible, others can be anything but discreet. If you’ve ever noticed a sulfur smell in water, you’ve experienced this reality firsthand. The unpleasant odor, which resembles that of a rotten egg, is not something you’re likely to be able to ignore or get used to. Moreover, you shouldn’t have to.
If you’ve experienced this odor problem, you may be wondering why it’s happening and what you can do about it.
Perceptible water quality issues may indicate the presence of a contaminant or other water quality problems.* Along with strange odors, you may sometimes observe discoloration or a strange taste in your water.
The smell of sulfur or even a chlorine odor may not necessarily indicate that your water is unsafe to drink. However, if you do find that the scent, taste or appearance of your drinking water has noticeably changed, it’s important that you have it tested to discover the source of the issue. This will help you learn if there is anything potentially harmful in your water and assist your efforts to identify treatment options, even if it’s safe to drink.
If your water smells like rotten eggs, that likely indicates the presence of hydrogen sulfide gas. This could be due to a problem with your water heater or naturally occurring sulfur bacteria, especially in well water. These issues can produce hydrogen sulfide, which leaves an unpleasant scent wherever it goes. Tap water that contains hydrogen sulfide gas or sulfur bacteria is sometimes referred to as sulfur water.
Noticing a rotten egg smell and any other potential issues with your water?
Find out what’s going on and how to fix it – try our Water Solutions Finder.
Hydrogen sulfide gas, which smells like rotten eggs, may occur naturally in well water. Less commonly, it could be due to a direct source of pollution. Most frequently, however, the smell of sulfur in your water is likely due to the existence of sulfate-reducing bacteria, which produces hydrogen sulfide as a byproduct.
Even small amounts of hydrogen sulfide can lead to the smell or taste of sulfur in drinking water. Texas A&M University noted that, at a hydrogen sulfide concentration of just 0.1 milligrams of hydrogen sulfide per liter, most individuals will notice the smell.
At the most basic level, it’s important to understand how hydrogen sulfide gets into your water, since that’s where the sulfur taste and smell comes from.
Usually, this emerges because of a combination in your water of both sulfate, which is a naturally occurring element found throughout the environment, and the presence of sulfate-reducing bacteria. These microorganisms produce hydrogen sulfide as a byproduct when the bacterium feeds off of the sulfate, reducing the sulfate to sulfide.
An electric water heater may also inadvertently produce hydrogen sulfide. Typically, these water heaters include a magnesium anode rod (made of magnesium sulfate) to help prevent corrosion of the water heater. If this anode rod corrodes, this can result in the production of free electrons in the water, which stimulate the reaction between sulfate-reducing bacteria and sulfate that produces hydrogen sulfide (and therefore the rotten egg smell). This is more likely to occur when water is left in the water heater for a period of time, and can go away once the water in the heater is used. In more severe cases, this could happen overnight and may require a water treatment system to eliminate the root cause (the bacteria).
Treating water for hydrogen sulfide requires you to identify which underlying conditions are setting the stage for the unpleasant smell of sulfur that your household is experiencing. A specialized water filtration system will likely be part of your comprehensive solution and can help you address other possible contaminants, too.
If hydrogen sulfide isn’t naturally present in your water, discovering the root causes that lead to the creation of this substance can help you determine the best next steps to address the problem.
In addition to the issues posed by a magnesium anode, the warm water found in your home’s water heater tank can create a suitable environment for sulfur bacteria, leading to contamination. This elevated sulfur bacteria presence can produce more hydrogen sulfide. Working with a professional to permanently raise the water heater’s temperature, or to undertake occasional flushing, can kill off the bacteria.
If your well water has that characteristic rotten egg smell, the origin of the problem may lie directly in your water source. For a groundwater issue, treating the water directly is the surest way to reduce the hydrogen sulfide causing the probleml. Working directly with an experienced water treatment expert to treat your well water with a specialized solution can address concerns that are related to well water quality.
Just understanding why your water smells funny doesn’t change anything, but finding out exactly what’s in your drinking water is essential for discovering which water treatment system options will work for you. Get started by scheduling a free in-home water test today.
*Contaminants may not necessarily be present in your water.
Get better water in your home by scheduling an appointment with your local Culligan Water Expert.
Be prepared - review these important tips to navigate an emergency that could impact your water.
Here are a few approaches that work — and a few that don’t.
With any of our soft water systems, get more out of your water-using appliances while spending less on energy and detergent.
See Water Softeners
There’s never been a better time to enjoy the convenience of scheduled bottled water deliveries from the Culligan® Water Experts
See Water Delivery Options
Culligan’s water filtration systems have improved water quality for thousands of families worldwide.
See Water Filtration Systems