Why Does My Water Smell Like Eggs/Sulfur?

Why Does My Water Smell Like Eggs/Sulfur?
You turn on the tap looking forward to a fresh glass of water, and it hits you - the nasty smell of rotten eggs. Unless you’ve recently flushed a plate full of breakfast down the drain, the unwelcome surprise is most likely the reek of hydrogen sulfide.

Hydrogen sulfide gas and sulfur bacteria are found naturally in well water and water supplies throughout the country. Even trace amounts can cause the characteristic rotten egg smell. While unpleasant, its presence in your water is unlikely to be a health hazard. If you want to rid your home of this nuisance, successful treatment depends on identifying the source of the contamination: is it the water supply, or your plumbing and appliances?

Is the odor coming from both the hot and cold faucets?

To investigate the root of your issue, alternate turning on the hot and cold water faucets and answer the following:
  • Does the smell flow solely from the hot water faucet? If so, the problem is likely in your water heater.
  • Is the smell in both hot and cold water faucets, but goes away after you run it for a while? The source is likely sulfur bacteria in your drain or plumbing.
  • If you have a water softener, does an unsoftened water tap, such as an outside garden hose spigot, smell too? If not, the issue may be sulfur bacteria in your water softener.
  • Is the smell in both faucets, and doesn’t go away? The source of the issue is likely hydrogen sulfide in your water supply.

What to do if your water smells like rotten eggs

To treat your sulfur odor issue, follow up on the likely source.

Odor in hot water only: Check your hot water heater. If it’s been idle - for example, you just returned from vacation - it’s possible bacteria has grown inside the water heater. Sanitizing the tank and flushing the water heater may get rid of the smell. Another possible issue with a hot water heater is the magnesium anode rod used to control corrosion interacting with sulfates to produce hydrogen sulfide gas. Changing the anode rod may resolve the issue, but may also void your product warranty. For either issue, it’s a good idea to contact a licensed plumber to help you treat the issue.

Odor goes away after running water for a while: Organic matter may have accumulated in your drain, acting as a food source for sulfate reducing bacteria, which produces hydrogen sulfide gas. To verify the issue is in your drain, not the water itself, fill a glass with water, and bring it into another room. If you don’t smell the odor in the glass anymore, the problem is in your plumbing. Flush and disinfect the drain yourself by pouring ½ cup of baking soda down the drain, followed by ½ cup of vinegar. After 15 minutes, pour in hot tap water to flush out the drain.

Odor in softened water only: Sulfur bacteria is attracted to the sodium in water softener brine tanks, and may grow over time. Clean and disinfect your brine tank on at least an annual basis.

Odor in both cold and hot water, odor does not diminish when run water: This scenario most likely points to hydrogen sulfide in your water supply. You will want to test your water supply to confirm if you have sulfur and potentially other issues such as iron, manganese, or bacteria, and may need to invest in a whole home filtration solution specifically for treatment of hydrogen sulfide.

Is hydrogen sulfide in water dangerous?

The smell of rotten eggs in your water is obviously unappealing, but it’s not necessarily a problem that will affect your health.

Can I drink water with sulfur?

Sulfate may have a laxative effect that can lead to dehydration and is especially dangerous for infants. The Environmental Protection Agency (EPA) standard for drinking water sets the maximum contaminant level for sulfate to 250 parts per million (ppm). Infants should not be given water with a sulfate concentration above 400 ppm.

You can easily test your water to determine the level of sulfate contamination. High levels of sulfate in well water can cause hydrogen sulfide by the action of sulfate-reducing bacteria.

There is not an EPA drinking water standard for hydrogen sulfide, because a concentration of hydrogen sulfide high enough for it to be a drinking water hazard would also make the smell and taste too unpleasant to drink. However, water with as little as 0.5 ppm of hydrogen sulfide is detectable by most people. Water with less than 1 ppm may smell “musty”, while 1-2 ppm is a typical range for the rotten egg odor. The level found in most household water is usually not a health risk, unless in very high concentrations, which is very rare. As hydrogen sulfide is a gas, it must be tested on-site.

Can I shower with water that smells of sulfur?

If your showerhead sprays out a sulfur smell, you’re most likely not at risk of ill effects. The exception would be if the level of hydrogen sulfide gas was exceptionally high in a small space such as an unventilated bathroom. If you’re concerned, test your water. If the level of hydrogen sulfide is above 1.3 ppm, reduce the length of showering to 10 minutes or less, and ventilate the bathroom. You may also want to consider investing in a filtration treatment for your water supply.

Will water containing sulfur ruin my clothes or dishes?

While not typically a health hazard, sulfur can be corrosive to metals such as iron, steel and copper. It also creates a black tarnish on silverware and stain copper or brass utensils.

If you use bleach in your laundry, the chlorine may react with untreated hydrogen sulfide to form a yellow film on your clothing and fixtures.

You can get rid of the rotten egg smell in your water

The unwelcome smell of rotten eggs in your water is a symptom of the presence of hydrogen sulfide or sulfate-reducing bacteria in your home’s plumbing or water supply. By diagnosing the source of the smell, you can figure out the proper treatment to solve the issue and enjoy the clean, fresh smell and taste of healthy natural water.