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

  • Sulphur or "rotten egg" odors in water throughout a home: if your water source is picking up sulphur, either seasonally (such as when water tables drop) or all year, you have a persistent sulphur source and the odor will be present at all plumbing fixtures in the home, possibly appearing stronger when water has not been run for some time - but see other versions of that clue which we discus below.

    Our photograph at above left, courtesy of Arlene Puentes, shows black sulphur bacteria and debris in a toilet tank in a home served by a well which was very high in sulphur.

    Since the toilet is supplied with cold water we knew this was a sulfur problem in the water supply, not simply a water heater anode problem.

    We provide a detailed list of sewer and sulphur gas odor sources

    Also CHINESE DRYWALL HAZARDS discusses Chinese drywall odors, sulphur smells, and corrosive outgassing hazards in buildings. Major costs to remove this product, repair or replace electrical wiring, plumbing, and HVAC components may be involved, and there may be immediate safety hazards due to damaged smoke detectors or carbon monoxide detectors in buildings where Chinese drywall outgassing has caused damage.
  • Sulphur odors only at certain fixtures: In certain instances, someone in the household may complain of a sulfur odor in one part of the home, but not any other. This is usually explained because of the presence of sulfur reducing bacteria in a "dead leg" in the plumbing system. These bacteria are not typically pathogenic, or disease-causing, and one common type would be Desulfovibriole.

    If there is a portion of plumbing that has been cut and then capped off, creating a small area of non-circulating water, or a "dead-leg", then these bacteria can get a foothold and metabolize the available sulfur in your water - creating a strong odor from one particular sink or tap.
  • Sulphur odors from water heaters: A frequent source of a sulphur-like odor in home water systems, regardless of whether your water is from a private well or from a municipal supply source, is a deteriorated sacrificial anode on the water heater tank.

    This anode, usually inserted into the water tank from its top, is intended to reduce water tank corrosion. Sacrificial anodes on water tanks can be replaced. If the odor is present only in your hot water, ask your plumber to try replacing the anode. We discuss the hot water tank sacrificial anode and dip tube in more detail at

    Watch out: as we explain
    at HYDROGEN SULFIDE GAS, hydrogen sulfide gas is dangerous and can explode or catch fire. Sewer gases also probably contain hydrogen sulfide gas (H2S) In addition some writers opine that there are possible health hazards from sewer gas exposure, such as a bacterial infection of the sinuses (which can occur due to any sinus irritation). Hydrogen is extremely flammable (easily set fire or explodes).
  • Hydrogen sulfide release from hot water: Another source of sulphur odors in water the energy which water heaters add to water in the form of heat. Increasing the temperature of water will also facilitate the release of hydrogen sulfide. In addition, the simple act of running water at a shower or faucet will cause a release of this sulfurous odor because of the agitation of the water being released from the tap.
  • Manganese or Iron, and Gallianella bacteria as a water odor source: If your source water is high in iron and or manganese, then you may have odors that emanate from bacteria like Gallianella. These naturally occurring bacteria can feed from the available stream of iron and manganese in a water supply, creating foul odors and sometimes plugging, or bio fouling water filters and well.

    Odors from iron or manganese-loving bacteria may resemble diesel fuel, heating oil, cucumbers, or sewage.

    A BART, or Biological Activity Reaction Test can determine if this type of bacteria is present in your water supply. You probably can't get rid of them because they are normal flora, (naturally occurring bacteria), but annual chlorination of your well will help keep them in check.
    See WATER STAINING CONTAMINANTS for more about manganese or iron in water.

    An ultraviolet disinfection system can disinfect the water as it comes into distribution to remove bacteria within the system. Chlorination may also be used, but is not a great choice if there is a lot of iron and manganese, as the chlorine will precipitate the metals out of solution and discolor the water.
  • Water Softeners as a source of rotten egg smells in water: if your source water from an outside spigot of un-treated water at your building does not smell, but if all of the water in your building, both hot and cold, smells like rotten eggs or sulphur, and if you have a water softener installed, it may be that you need to sanitize your water softener equipment. This problem is more likely to occur if the water softener has been shut down for a week or more, such as when you are restoring a winterized building to service.

    See SOFTENER ADJUSTMENT & CONTROLS for the procedure to follow for sanitizing a water softener.
  • Other sources of sulphur odors: Does your water smell when you return from vacation? Non-use of a regular water line can also create the same condition of sulphur odors.
  • We provide a detailed list of sewer and sulphur gas odor sources
    at Sources of Sulphur Odors in Buildings.

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



Continue reading at WATER ODOR TREATMENTS, CURES - SULPHUR or select a topic from the More Reading links shown 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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WATER ODOR DIAGNOSIS - SULPHUR at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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