How Do I Fix Rotten Egg Smell In Well Water?

Eric Roy, Ph.D.  |  Scientific Founder

If your home draws water from a well, you may have experienced rotten egg smells coming from your water. While not typically harmful, offensive odors are nuisances, and can usually be fixed. In this article, we talk about common causes of tap water odors, how we troubleshoot odor problems, and talk a bit about how the problem can be fixed with a filter.

The Likely Culprit: Hydrogen Sulfide!

Rotten egg smells in water are usually caused by volatile sulfur-based chemicals (e.g. hydrogen sulfide), which are produced by naturally-occurring bacteria as part of their metabolism. (For those who just Googled “Hydrogen Sulfide” and saw hazard warnings… keep in mind that while hydrogen sulfide is harmful at very high concentrations… it’s highly unlikely that your water could generate high enough levels in your home to cause health problems). With that said, no one wants their home to smell like rotten eggs, so it’s a problem worth fixing!

Hydroviv’s “Toilet Tank Test” For Rotten Egg Smell

The first thing we do when a customer comes to us with a smelly water problem, is to have them take the lid off their toilet’s tank and take a few pictures that can be sent to us (I’m not kidding!). The toilet tank is a great observation point for us because it’s typically the most accessible place in the home where water is constantly resupplied from the source and is rarely cleaned out (though many start cleaning the tank after taking the lid off for the first time).

We examine the pictures to look for clues for what’s going on in the water. For example, if the tank has slimy, rusty deposits, there’s a good chance that the smell is being generated by iron bacteria. If there are brownish/black deposits visible, the water probably has high levels or iron and/or manganese. 

Case Study: 

A family came to us because their water “smelled like farts” and they were sick of replacing inexpensive carbon filters every week or two. While carbon filtration is a great base technology to use in a wide range of applications, inexpensive cartridges use low quality filtration media with very low capacities for hydrogen sulfide. Unfortunately, (or fortunately…depending on how you look at it), it’s obvious when a filter becomes saturated with hydrogen sulfide…because the rotten egg smell comes back…immediately…in full force.

We ended up formulating a custom water filter for this customer with an extra high capacity for hydrogen sulfide, and the difference was dramatic. Instead of switching out cheap carbon filters every 10-14 days, the customer was able to use the same Hydroviv filter for 6 months, which saved them a great deal of money in replacement filter costs, not to mention the added convenience of not having to change out a filter every 10 days! It was great to get the excited monthly email updates from the user, letting us know that the filters were still going strong! Once they were confident that we could solve their problem, the customer also purchased some shower head water filters to fix rotten egg smells in the bathroom!

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