How to Remove Sulfur From Your Well Water

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While most people get their drinking water from public water supplies, more than 13 million households in the United States rely on private wells for their drinking water. Well water can absorb many different compounds from the surrounding soil — and when levels of compounds like sulfur get too high, you’ll need to filter it. If you’re dealing with high levels of sulfur in your drinking supply, learn how to remove sulfur from well water.

What Is Sulfur and How Does It Get in Well Water?

Sulfur is a naturally occurring chemical compound. There are two sources of sulfur in well water – sulfates and hydrogen sulfide gas.

  • Sulfates are a type of salt that contains sulfur. They may be in the soil and rocks surrounding your well. As groundwater and rainwater seep through the soil and rocks, they can carry sulfates into your well water.
  • Hydrogen sulfide gas (H2S) can happen naturally when plants or other organic material decays. It can also be related to pollution in the water. And when sulfur bacteria feed on sulfates in well water, they can create H2S. You’ll need to remove the H2S from your water and vent the gas from low-lying spaces around your well. 

Is Sulfur Harmful?

It depends on the level of sulfates or hydrogen sulfide in the water. In small amounts, these things don’t cause a problem. 

Too much sulfate can cause diarrhea and dehydration. It can also have a bitter taste, clog your pipes with slime and stain your laundry. 

Too much H2S causes a rotten egg smell in well water. In large amounts, it can be poisonous and lead to nausea and illness — but this is more likely to happen from breathing the gas than from drinking water. H2S can also corrode pipes and stain your utensils.

How Can I Tell If My Well Water Has Sulfur?

There are a few ways to tell if you have a sulfur problem:

  • Smell or taste — Sulfur has a distinctive smell similar to rotten eggs, and sulfates can give water a bitter taste. If your well water has sulfur in it, you may notice an unpleasant smell or odd taste.
  • Slime or stains — Sulfur bacteria can leave black stains or a white, grey, black or reddish-brown slime on silverware or plumbing.
  • Water tests — Get your well water tested every year, even if you don’t notice signs of sulfur or other problems. You can find several different water testing kits online or in stores. But to ensure accurate results, find a state-certified laboratory to do the tests. And check with your local health department first, in case they provide these tests for free. 

How Can I Remove Sulfur From My Well Water?

There are many options for removing sulfur from your well water. The best option for you will depend on the source of the sulfur, how serious the problem is and how much you’re able to spend. Options include:

  • Activated carbon filtration — Activated carbon filters use small pieces of porous carbon (like charcoal) to attract chemicals in water and filter them out. You can install an activated carbon filtration system as a low-cost and low maintenance solution to remove a low concentration of sulfur — but it won’t handle high concentrations of sulfur.
  • Aeration treatment — This is a low-cost and safe solution that adds air to the water. This process may reduce the hydrogen sulfide to acceptable levels, but may not get rid of it completely. And it won’t kill sulfur bacteria.
  • Chlorine bleach — You can inject chlorine bleach into your water before filtration. This is a low-cost solution that can effectively remove medium-to-high levels of hydrogen sulfide from your water. But this method isn’t fast-acting, and it also adds sodium to the water and can leave toxic residue. 
  • Potassium permanganate — You can use potassium permanganate solution in combination with a special type of filter to remove sulfur particles. This process gets rid of several odors, but it can be toxic and may leave your water looking pink.
  • Hydrogen peroxide — This is a fast and safe solution that leaves no chemical residue and no taste in the water. But an annual supply of peroxide may be expensive, so it’s not as common in private home water systems.
  • Ozone gas — This is also a fast and safe solution that leaves no chemical residue. But ozone systems are expensive, and they add gases to the water that you then need to vent.

If you own a private well, or are thinking of putting one in, check in with your local health department about maintenance procedures to make sure your water is safe for everyday use. Many health departments offer free water testing to check the levels of sulfur and other compounds — and they can provide more detailed advice about the best filtration methods.