• Sulfur is a naturally-occurring element that produces a nasty smelling gas in domestic wells.
  • While the sulfur found in most wells isn’t considered dangerous, many compare its smell to rotten eggs. So it’s no surprise that well owners want to remove it.
  • However, most people find that standard cartridge or carbon water filters aren’t effective at removing sulfur.
  • This is because sulfur gas needs to be oxidized before it can be filtered from the water supply.
  • To oxidize and remove sulfur from water, use an injection filter system.
💡 Our favorite injection filter system is the SpringWell WS1.
How to choose a well water filtration system


Here’s why your current cartridge or carbon water filter isn’t fixing your sulfur issue, and how to set up a better filtration system that meets your needs.

SpringWell Air Injection Well Water Filter

  • The top rated well water filter in our 2023 review
  • Removes 8 PPM hydrogen sulfide
  • Reviewers says rotten egg smells are eliminated
  • Also removes iron and manganese stains
  • No replacement cartridges necessary
  • A high flow rate for use with multiple faucets

Why is my well water contaminated with sulfer?

If your well water has a sulfur aroma, you’re not alone. Many homeowners across the US struggle with sulfur contamination. This is normally due to one of two reasons:

  • Sulfur has found its way into your well from bedrock, surface water runoff, or the surrounding earth.
  • The rod inside your water heater has corroded and is releasing sulfide gases.
Source Where does the sulfur come from?
Bedrock Groundwater can naturally contain sulfates. Of all types of bedrock, sandstone and shale are often the most prone to releasing sulfur odors in the water supply.
Decay In ecosystems with lots of dead vegetation, hydrogen sulfide gas can be released as part of the decaying process and mix with surface water.

There are several types of soil-dwelling bacteria that feed on sulfates and release hydrogen sulfur gas as a waste product. When bacteria live in or near a well, this gas can become trapped in the water supply.

Water heater When a water heater is used in conjunction with a water softener, the softening process can affect the magnesium rod inside the heating unit. Soft water can erode the magnesium and produce hydrogen sulfide.

How to identity sulfur in well water

  • Rotten egg smells
  • Black staining on laundry
  • Pipe corrosion
  • Water heater corrosion

The most accurate method of sulfur identification is a well water test. There are at-home tests designed specifically to look for sulfur. You can find them online for $20-50.

To check whether your water heater or your environment is causing sulfur contamination, compare your hot and cold water supply.

If only heated water shows signs of sulfur, you can assume that the issue is coming from the heater.

Why won’t my cartridge water filter work on sulfur?

Whether they’re kept in the refrigerator, attached to a sink, or plumbed into your home’s main water line, most water filters work using replaceable cartridges.

Inside these cartridges is a mix of screening materials to capture undissolved particles, and granulated filter media that adsorb or attract dissolve substances.

The most common granulated filter media is made from activated carbon: highly pure charcoal blocks that are designed to filter organic contaminants.

Carbon block filters

Activated carbon filters are the most common type of filter found in homes across the country.

If you have a water filtration system at home, there’s a good chance that it uses activated carbon as its primary filter media.

Why won’t carbon filters work for sulfur? ❌

Carbon filters do an excellent job of removing many common causes of bad smells in drinking water, but they won’t remove significant amounts of sulfur.

For a carbon filter to absorb any sulfur, that sulfur needs to be oxidized (see next section). The majority of sulfur found in domestic wells is not naturally oxidized.

What about water softeners? ❌

Some internet sources claim that water softeners can be used to remove sulfur from well water.

This isn’t true—at least when it comes to traditional devices.

What about KDF filters? ~

Another less common type of cartridge filter is copper-zinc, otherwise known as KDF (Kinetic Degradation Fluxion).

KDF cartridge filters do oxidize contaminants like lead, iron, and hydrogen sulfide, so they are able to remove sulfur from the water supply.

However, if you have a significant sulfur issue, KDF cartridge filters are generally not the best value choice. Instead, think about a copper-zinc tank filter such as the Aquasana Rhino.

While tank filters like the Rhino can be significantly more expensive to buy than cartridge models, they last for 6-10 years, are more reliable, and don’t require replacement cartridges.

This means that overall value for money is almost always higher in a tank system versus a cartridge system when you take into account all the costs over the lifespan of the filter.


Be careful when choosing a cartridge filter to tackle sulfur, even if it contains a KDF stage and calls itself a “Sulfur Filtration System” or a similar name.

These devices may remove small amounts of hydrogen sulfide and other contaminants, but they don’t offer great performance or value for money.

Instead, think about a tank KDF filter—or better, one of the injection filters below.

How to reduce sulfur in well water

When it comes to reducing sulfur levels in well water, you should look for injection filters that first oxidize, then remove sulfur gases.

There are two main types of injection filtration systems: air injection and chlorine injection.

Air injection filters ✅

Air injection filters introduce air pockets (containing oxygen) into the water supply, which oxidizes any sulfur gas drawn from your well.

Once oxidized, hydrogen sulfide becomes insoluble, which allows the injection filter to effectively remove it.

Air injection systems will either perform the sulfur oxidization and filtration stages in separate tanks, or they may combine both into a single unit.

By the same process, air injection filters are also an excellent choice for removing other common well water issues, such as:

  • Water discoloration, bad tastes, and staining due to iron
  • staining caused by manganese

Chlorine injection filters ✅

Sulfur gas also oxidizes when in contact with chlorine. So, even though the chemical is usually associated with disinfecting water, it can also be used to remove sulfur from private wells.

Chlorine systems usually inject chlorine using a feed pump with a meter that regulates deposits. Some combine well water with chlorine in a dedicated tank to increase contact time.

Once oxidized, chlorine injection filters remove sulfur with a filter media in just the same way as air injection filters.

If the system uses lots of chlorine, it may also include an extra carbon filtration stage, which is the most effective way to remove excess chlorine in your drinking water.

Which type of injection filter is best for me?

Chlorine injection systems are often rated to remove very high levels of sulfur gas, making them a good option if your well suffers from extreme sulfur contamination.

However, using a chlorine-based system means adding chemicals to your water supply, and monitoring your feed pump for regular refills.

We’ve also read a significant number of chlorine injection system reviews by people who are unhappy with how noisy their chlorine injectors are.

So, if your filter system is installed inside and near a bedroom, this may be frustrating.

For most people, we recommend air injection sulfur filters over chlorine injection filters:

  • Air injection filters are often cheaper than chlorine injection filters
  • They’re rated to remove high levels of sulfur than most well owners experience
  • It’s tried-and-tested technology
  • No added chemicals or replacement cartridges needed

Looking for a filtration system that removes Sulfur smells, Iron stains, and other nasty well water issues?

We’ve reviewed the best well water filtration systems currently available on the internet…

Extra: how dangerous is it to drink sulfur in water?

Sulfur contamination in drinking water is common and not considered a health risk, especially when levels of sulfur remain low.

That said, as levels rise, sulfur contamination can cause stomach upset and diarrhea.

People who are used to drinking sulfur-contaminated water are less likely to experience negative health effects, while those who never encounter sulfur may be sensitive to even small amounts.

Beyond the direct health risks, the presence of sulfur bacteria in water can affect the functioning of a well water system.

As bacteria grow, they clog pipes and increase sulfur levels to the extent where corrosion and staining occur.

Overall, the most common result of sulfur contamination is not a health concern, but an aesthetic one. At moderate levels, sulfur makes water smell and taste offputting, and the aroma can cling to clothes and linens washed in sulfur-contaminated water.