What To Do When Your Water Smells Like Rotten Eggs

When your water smells like rotten eggs, the last thing you want to do is take a big drink. The good news is that the common culprit — hydrogen sulfide gas caused by sulfur bacteria — can be addressed with the right kind of water filtration.

However, there’s more to the story. It’s helpful to know where the bacteria comes from, how it causes the rotten egg odor and whether this can indicate other issues in your water supply.

Here’s your guide to a sulfur smell in drinking water and what to do about it.

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How to Treat Sulfur Smells in Water

The first step in any kind of water treatment process is to uncover what’s really causing the problem. When it comes to a rotten egg smell, you’ll often find that sulfur bacteria is to blame — but you won’t know for sure without proper water testing.

A professional water test is a reliable solution for identifying and treating water quality problems. That’s because experts can make connections and interpret results in ways you might not be able to. Plus, a free water test only takes about 30 minutes and comes with personalized recommendations for next steps.

To treat a sulfur smell, your water expert will likely point you toward whole-home filtration. These systems go beyond drinking water to handle concerns that might impact cooking, cleaning, bathing and more — and this unpleasant odor is certainly on the list.

The key to this kind of water treatment is finding a system that has been officially tested and can address the underlying problem. Look for Water Quality Association (WQA) certification against National Sanitation Foundation (NSF) and American National Standards Institute (ANSI) Standard 42, which means the filtration solution can effectively reduce hydrogen sulfide and the associated odors.

Browse our whole-home filtration systems.

There’s one more thing to know about treating sulfur problems, and that’s the source of your water supply. While smelly water can be a problem for both city and well water users, sulfur bacteria is primarily a problem for the latter (see below for other potential causes that could impact city water). That’s because city water is often treated with chlorine, which can potentially kill the bacteria; private wells, meanwhile, aren’t managed or treated by any outside experts or authorities. That means there’s no chlorine bleach solution added to your water supply — so it’s up to you to identify and treat any possible problems.

The good news is that regular testing can help protect your well water quality. This also helps you catch other common well issues, including iron and hard water.

What Causes the Rotten Egg Smell?

When you turn on the tap and immediately pick up the rotten egg odor, what you’re usually smelling is a chemical reaction.

It all begins with sulfur. This chemical element is found everywhere, from plants and soil to volcanoes and hot springs. It’s tasteless, odorless and doesn’t dissolve in water — so it doesn’t make that unpleasant smell on its own. That only occurs thanks to sulfur bacteria, which can live in low-oxygen environments like groundwater, wells, plumbing systems and even your water heater. Although these bacteria play an important role in a natural cycle by breaking down sulfur, they also create hydrogen sulfide as a byproduct. This gas can be highly corrosive and often leads to taste and odor issues in drinking water.

Of course, plenty of similar chemical reactions happen every minute. This one is only a problem because our senses can pick up on very small amounts of hydrogen sulfide. In fact, just 0.05 milligrams per liter can have a noticeable taste. It takes a little more to create the odor — 0.1 milligrams per liter — but even that is the same as about 1 teaspoon of salt dissolved in 1,000 gallons of water. On top of that, these issues may get even more noticeable if you haven’t run your tap for several hours or when you’re using hot water.

Other Potential Causes of Sulfur Water Odors

Although sulfur bacteria creating hydrogen sulfide in your water supply may be the most common explanation for that rotten egg smell, there are other possible sources.

For example, 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. If the rod itself corrodes, it may create free electrons in the water, which stimulate the reactions responsible for hydrogen sulfide. This is more likely to occur when water is left in the water heater for some time and can go away once the water in the heater is used. However, this can happen overnight, too.

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. In this case, you might need to work with a professional to permanently raise the water heater’s temperature or undertake occasional flushing, which can kill off the bacteria.

Hydrogen sulfide also occurs naturally in the environment when organic matter decays. If this happens in or around your water source, you might smell the gas when you turn on your tap.

Finally, hydrogen sulfide gas can also be created by some kinds of pollution. This is rare, but it’s one more reason you should always get a water test to make sure you know where tastes and odors are really coming from.

Can You Drink Smelly Water?

In some cases, drinking smelly water is an unpleasant experience, but it’s not necessarily a health concern. In other cases, that odor could indicate a more serious problem.

For example, because of the chlorine in city water, you might notice a swimming pool odor when you turn on the tap. Some people find this unpleasant to drink, cook, clean and bathe with, but it’s not generally a health issue. Instead, it’s a sign that the chlorine is doing its job.

On the other hand, some smells can be cause for concern. There are two reasons for this:

• The contaminant responsible for the odor may lead to health issues.
• The contaminant may indicate the presence of separate issues and impurities.

The first case is somewhat rare; examples include gasoline or turpentine smells, which indicate that a pollutant has made its way into your water supply. The second case is more common — and that’s where sulfur odor lands.

Sulfur bacteria aren’t generally harmful. However, they can create slime that clogs plumbing systems and builds the perfect environment for other bacteria. These can lead to additional unpleasant tastes, odors and colors, and some can even grow organisms that might cause diseases.

On top of that, hydrogen sulfide gas in your water can corrode pipes and other parts of the plumbing system over time. This can cause more problems for your water supply, from metallic tastes to potential lead, iron and copper contamination.

So, what does this mean for the overall safety of smelly water? The takeaway is simple: It’s never a good idea to assume that a water quality problem is safe to ignore. Instead, consider having a professional water test performed. This will help identify what’s responsible for the odor, whether you should be concerned and what treatment options are a good fit.

The same is true for other issues like odd tastes and appearance. Even if the contaminant or problem causing these symptoms is unlikely to impact your health, it could create an environment where more concerning impurities are allowed to flourish. Without a water test, you’d never know for sure.

But that doesn’t mean your water is perfect if it’s without odor, taste and other noticeable issues. Many contaminants like lead and arsenic have no noticeable signs, which means relying on your senses alone isn’t enough to gauge your water quality. That’s one more reason a water test is the best way to go.

FAQs About Water Quality

Want to learn more about water quality issues like sulfur odors? Here are a few FAQs:

Is City Water Safe From Hydrogen Sulfide?

Because city water is chlorinated, it doesn’t often come with rotten egg smells. However, it’s important to remember that city treatment can’t address every possible water problem.

For example, some issues are still being studied, which means treatment plants may not be targeting them yet. “Forever chemicals” fall into this category, although recent U.S. legislation will require public water systems to adhere to a new drinking water standard intended to limit exposure. Microplastics are another type of contaminant that may still be present in city water.

Are There Other Treatment Options?

While whole-home filtration might be the recommended solution for tap water that smells like sulfur, other issues require different kinds of treatment. A water test will help you determine what your problems are, what’s causing them and whether a process like reverse osmosis filtration would be a better fit.

Does Softening Remove Sulfur Bacteria?

Softening is an important process, but it’s not the same as filtration. The former targets calcium and magnesium, which cause hardness and a host of related issues like limescale and dry skin; the latter addresses a range of contaminants and impurities depending on what method is used. However, these separate systems often complement each other and can improve all your water experiences.

Take the First Step Toward Better Water

A sulfur smell in your drinking water can seem concerning, and while it’s generally not a health risk, it can indicate other issues. If you’ve noticed this issue or any other taste, odor or color concerns, it’s time for a water test. Your local Culligan water expert can walk you through the results and make personalized recommendations that will have your water looking, smelling and tasting fresh.

Get started by scheduling a free in-home water test today.

*Contaminants may not necessarily be present in your water.