WATER QUALITYThe Causes of Hydrogen Sulfide in Your Drinking Water

April 4, 2022

Hydrogen sulfide gas gives off the infamous “rotten egg” smell and taste in water. Hydrogen sulfide or sulfur bacteria can cause other problems. It can cause slime, other bacteria, clogs, black stains, dirty fixtures and corrosion of plumbing pipes and parts. What causes hydrogen sulfide in your drinking water?

Is Hydrogen Sulfide in Water Bad for You?

Sulfur is not harmful, no matter how awful it smells. Hydrogen sulfide gas, though, is hazardous in high levels. If there’s gas in the air or water, you need to act ASAP to remove the gas. You need to vent the gas to outside a home, building or enclosed area.

While rotten egg water is terrible, it doesn’t necessarily mean the water is unsafe or of bad quality. Gas though may be in the water due to sewage or contaminants and those are dangerous and not safe. If you’re thinking hydrogen sulfide or sulfur bacteria is in your water, you should have it tested.

How Does this Stuff Get into My Water?

How do these gases get into water? It can happen naturally in groundwater due to decaying vegetation or rock giving off minerals, including sulfur. Sulfur bacteria can get into well water or sources of public tap water. Hydrogen sulfide and sulfur can come from pollution.

These gases can also be made, quite literally, in a water heater in your home. Bacteria can grow inside warm, wet environments. The chemical reaction between the metal, magnesium, rod in a water heater and water, or slight particulates or contaminants in the water, can cause this problem.

Can I Tell if Hydrogen Sulfide’s In My Water?

The first sign is likely to be the smell. Hydrogen sulfide gas has a bad odor even at a low level. One thing to take note of is, is the smell from hot and/or cold water? The odor is more apparent in hot water because it will put a larger amount of gas into the air.

If you’re getting the smell just from hot water, the gas is probably coming just from your water heater. If it’s coming from cold and water water, seemingly equal, the issue is probably sulfur bacteria in the water source – be it public water supply or a well. Or, if it’s from both temperatures, it could be hydrogen sulfide gas. If you’re using a water softener, and the odor is from hot and cold water, you could have sulfur growth in the water softener.

If you think gas or other contaminants are in the groundwater, you may contact a water treatment specialist and a pro can test the water, measure the gas or other content from the water in your home. Then you and the expert can work together on the best ideas for your home’s water supply.

Removing Hydrogen Sulfide from Water

Once you’ve figured out the gas or substance in your water and the cause of the gas, you can get to treatment options for your water. It’ll depend on if your water source and where the hydrogen sulfide or sulfur is coming from.

If the gas is coming from the well or public water source, the likely treatment will be disinfecting the well or your plumbing. You or a pro can disinfect a well or plumbing system with chlorine. This is called “shock chlorination.” The higher step for a worse scenarios is physically washing the well, using stronger treatment chemicals or using agitation plus treatments to disinfect it.  The worst scenario is drilling a new well.

In a water softener device or another filtration device, you might need to disinfect or replace the system or a component in it.

An activated carbon filter might be effective for groundwater and relatively low levels of hydrogen sulfide in the water. This mode of filtration creates very clean water. Depending on your system, water usage and level of gas, though, carbon filters might not last long or be extremely effective against hydrogen sulfide.

The Causes of Hydrogen Sulfide in Your Drinking Water
If you’re thinking hydrogen sulfide or sulfur bacteria is in your water, you should have it tested.

Removing Hydrogen Sulfide in a Water Heater

Removing this gas from a home water heater can be a complex job. You can try the steps listed below. Working with a water heater can be a risk. If you’re unsure or inexperienced, or can’t safely take on a task, it’s best to contact a plumber or technician.

  • Replacing the magnesium rod

Most heaters have a magnesium rod. It’s inside the tank, connected to a plug at the top of the water water. Before doing another work, turn off the water to the heater. Release the pressure from inside the heater. Unscrew the plug. Plug the hole.

Be careful if you’re removing and replacing the magnesium rod. This can ruin the heater. A new rod can stop the hydrogen sulfide gas. A magnesium or aluminum rod provides corrosion protection within a heater, so it’s a necessary part.

  • Flushing the tank

You can disinfect and flush the water heater and tank with a chlorine bleach solution. You need to know how to safely and completely drain and flush a heater and tank to take on this task.

  • Hotter water

You can turn up the water temperature, to 160 degrees for a few hours, and this can kill bacteria and other contaminants. Then, flush the heater and tank to get rid of contaminants and the leftover smell. Note, make sure you know how to safely control the water temperature and no one will use the hot water while raising and adjusting the heater’s temperature.  


South End Water Filtration specializes in HALO Water Filter products including the HALO H2 Zero Whole Home Water Filter. HALO systems solve hard water problems, give your family clear, great-tasting water and are totally maintenance free. We’re just a click away to help and answer any questions. South End Plumbing and South End Water Filtration will give you a free estimate. Call us at 704-486-1988 or contact us online to schedule a visit.