Photograph of brown stained water in a building. How to Identify & Cure Sulphur Smells or Odors in Drinking Water

  • WATER ODOR DIAGNOSIS - SULPHUR - CONTENTS: How to get rid of or treat stinks, smells, rotten egg odor, sulphur odors in water. How to diagnose the cause of rotten egg sulphur odors in drinking water. What are other common odors in drinking water and what causes them? Health risks associated with some water odors? How to get rid of other odors in drinking water
  • POST a QUESTION or READ FAQs about the causes & cures of odors or smells in water supplies

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Water odor diagnosis & cure:

This article discusses how to identify, diagnose, and cure rotten egg or sulphur odors in drinking water.

We also discuss which of these odors may warn of unsanitary conditions. Edits, content addition, & web page design

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Diagnosing and Correcting Sulphur Odors in Water

ISulphur debris in a toilet tankf your source water runs through an area where naturally occurring sulfur is present, some sulfur may dissolve into the water. We provide a diagnostic procedure to track down the source of sulphur smells in water just below.

Some of this dissolved sulfur turns to the gas, hydrogen sulfide, and this can give the water a rotten egg type smelly odor.

Sulphur odors can also be caused by a failing hot water heater component, or by certain bacteria in the building plumbing system, conditions we also discuss below.

Sulphur smells in water can also occur in rivers, lakes, streams, ponds, and can be caused by anoxia and algae which in turn may be caused by high nitrogen from agricultural runoff - a condition we discuss

Watch out: methane odors in a building water supply can be explosive -

Watch out: Sulphur smells, rotten egg smells, or sewer gas smells can be caused by a variety of problems that we describe here. The sulphurous odor may be due to sulphur in the building water supply, bacteria in water, deteriorating water heater electrodes, dangerous sewer gas leaks, hydrogen sulfide gas forming in the water heater itself, even contaminated drywall or perhaps human or animal flatulence. Some of these gases and the implications of their source can be very dangerous, as we describe here and in related articles.

What if the Sulphur Odor is Not Traced to the Water Supply?

If the source of rotten egg smells or sulphur in your building is not traced to a water supply problem, see these related articles

Health Effects of High Levels of Hydrogen Sulfide in Water

H2S in water range from none to very low (0.5 ppm) to "rotten egg smell" (1-2 ppm), to typically about 10 ppm in many water wells. In some water wells H2S may be detected at much higher levels in the 50-75 ppm range.

In the U.S. the U.S. Environmental protection agency does not regulate the level of sulphur in primary or secondary drinking water. Why? In concept, a concentration of sulphur or hydrogen sulfide in water high enough to be a health concern makes the water so nasty smelling that it is considered un-palatable: people won't drink it. Even very low concentratoins of hydrogen sulfide in water, in the 0.05 ppm range, can be detected as an odor by most people. Low levels of H2S (hydrogen sulfide) in water impart a musty odor that some sources describe as "swampy" smelling water.

Watch out: for corrosive effects of high levels of H2S in water. Higher levels of H2S in the 1-2 ppm range will impart the "rotten egg" smell that most people use to describe the odor. If your water supply smells like rotten eggs and if the odor is in the water source (not from other causes such as bacterial contamination or a problem in a dirty water softener or water heater), then the water is also highly corrosive to plumbing.

Question: Kinetico water softener backflushing to reduce water odors

(July 25, 2016 Re-posting from private email

A few years ago I had a Kinetico water softner system installed at my house by a reputable company. Tremendous improvement over the older system. I was advised by the installer to backflush the resin tank once a month with a gallon of professional grade peroxcide.

Then spin it back and flush with a gallon of pool chlorine and run the water until clear. Naturally, changing the filter also

I've been doing this for years with good results. I change the carbon bed every 1 1/2-2 years.

My water never has an odor until now, a month to the day from the last cleaning. Am I missing something?

Here in Florida we have recently had heavy rains and stifling humidty. Thanks - E.G.


E.G. If the new odors are in your incoming water supply that might mean we need to amend the whole water treatment system.

If the odors are not in the incoming water supply but only occur in water passing through the water softener, the carbon bed may be contaminated and need replacement.


Continue reading at WATER ODOR TREATMENTS, CURES - SULPHUR or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.



Or see WATER STAINING CONTAMINANTS for discussion of water contaminants that result in stains on fabrics, fixtures, etc. and that may also help diagnose some water odors.

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