Will A Water Softener Remove Sulfur Smell? September 8, 2022 11:00

Will A Water Softener Remove Sulfur Smell?

water kettle with steam coming out

Foul-smelling or unusual odors from your water should make you question its quality and safety. Some odors indicate the presence of contaminants which may pose a health risk. Other odors, such as those caused by hydrogen sul- fide, are more of a nuisance, only affecting the taste of the water.

Why does my water softener smell like rotten eggs? It's your water supply. Sulfur in your water supply is easily recognized by its offensive odor. Hydrogen sulfide gas causes the "rotten-egg" or sulfur water smell. Hydrogen sulfide in water causes no known health effects. However, high concentrations do change the taste of the water.

Hydrogen sulfide dissolved in water corrodes metals such as iron, steel, copper and brass. The corrosion of iron and steel from sulfur forms ferrous sulfide or "black water." Hydrogen sulfide in water can blacken silverware and discolor copper and brass utensils.

Sulfur water makes cleaning clothes very difficult. Using chlorine bleach in sulfur water reduces the cleaning power of detergent. Hydrogen sulfide in water also corrodes exposed metal parts in washing machines.

Iron and manganese, often present with hydrogen sulfide, turn the water black and greasy-feeling. If untreated, the water stains laundry, washing machines, sinks and kitchenware. When used in the laundry, chlorine bleach reacts with iron and manganese forming dark rusty or brownish stains on clothes.

Why does my water softener smell like rotten eggs?

why does water smell like rotten eggs

Is it your water softener or potentially another source? When treating water to remove the odor, the first item on the “to do” list is to determine the potential source(s) of the hydrogen sulfide:

  • Odor on hot side only.

Run the hot water from each tap and notice if there is an odor in the hot water that is not apparent in the cold water. If you smell a “rotten egg” odor, this is hydrogen sulfide gas. If the water smells like oil or asphalt this can be from manganese. If your water smells like cucumber or sewage this is usually a result of iron and/ or sulfur bacteria. If there is only an odor in the hot water, this indicates a problem with the water heater. The most likely source is a reaction between an anode rod in the water heater and natural sulfate ions in the water. If the aluminum rod still produces the odor, the next step would be either to operate the water heater without an anode rod or to remove the sulfate ions. Removing the anode rod would remove its corrosion protection, potentially shortening the life of the water heater tank. There are FDA-listed corrosion inhibitors we can add to the water to extend the life of the tank. Removing the sulfate can be accomplished by using a dealkalizer, a system similar in operation and cost to a water softener.

  • Odor in the cold water that goes away after water flows. In this scenario, the most likely source of the hydrogen sulfide is Sulfate-Reducing Bacteria (SRB’s). The bacteria are not considered pathogenic, but they “breathe in” sulfate ions and “breathe out” hydrogen sulfide, just like we breathe in oxygen and breathe out carbon dioxide. Just like an un-ventilated room full of people can get stuffy after awhile, a section of plumbing where there is no flow can get stinky after awhile when SRB’s are present. Therefore, a characteristic of a rotten-egg odor due to SRB’s would be a strong odor in the cold water at first draw (for example, filling the pot for morning coffee), with the odor decreasing as the cold water flows. Although rare, it is possible for SRB’s to colonize in the water heater tank but nowhere else. The tank holds too much water for the odor to flush out quickly. A relatively easy test to determine if the water heater tank contains SRB’s is to raise the temperature to 140F or higher for 48 hours, which will kill the bacteria. If the odor (hot side only) goes away, the odor was due to SRB’s; if not, it is due to the anode rod reaction. Some laboratories can test for SRB’s, and field test kits also are available. Treatment would consist of shock-chlorination of the well and plumbing, with continuous chlorination if the odor returns too quickly.


  • Odor in the hot and cold water that does not decrease as the water flows. 

If there is an odor problem with the water supply, the first step is to determine the source. If the source is from the well, a general mineral water analysis is critical to selecting the right system to treat the problem.

The test should include analysis for pH, iron, manganese, hardness, total dissolved solids at a minimum. Other tests for sulfate, hydrogen sulfide and tannin are recommended as well.This is true hydrogen sulfide from the source aquifer. The choice will depend on the level of hydrogen sulfide and other contaminants (like iron) in the water as well as the peak flow rate (gallons per minute) and the peak daily water usage (gallons per day).

How do I get the sulfur smell out of my house?

sulfur smell in house

Ordinary household water softeners do not remove sulfur odors from water. In fact, softeners easily become fouled or clogged, reducing their softening capacity. Several methods of removing sulfur from water are available. The treatment method selected depends on many factors. These factors include the level of sulfur in the water, the amount of iron and manganese in the water, and if bacterial contamination must also be treated. Remember to consider the simplicity of the treatment method and the total cost including installation, maintenance, and chemical costs. When sulphur is the lone problem, a backwashing style sulphur filter that uses atmospheric oxygen and catalytic media is often the best choice. When sulphur is part of a more complex water issue (and especially when bacteria is present) chlorine or another chemical oxidizer may be added to the water source using a Stenner Chemical Feed Pump.

As with many water problems, the cause(s) may be complex and require in-depth exploration. For hydrogen sulfide, that exploration starts with finding the source. Whether the rotten egg smell is from only the hot water or cold water or both, if you are experiencing problems with well water smells, follow these simple steps.

 If you have rotten-egg sulfur smells in the hot water only, Replace the anode rod with an aluminum rod or powered anode. Add a Water Heater Odor Killer to make it easy to add store-bought hydrogen peroxide to the water heater.

If you have extreme sulfur odors from the cold well water, we recommend shocking the well with chlorine and then installing a peroxide injection system with a backwashing carbon filter. Chlorine bleach can effectively remove medium to high levels (over 6 mg/l) of hydrogen sulfide. The chlorine in the bleach chemically reacts with (oxidizes) the hydrogen sulfide eliminating the "rotten egg" odor. Chlorine bleach also reacts with iron or manganese and disinfects water supplies.

If you have sulfur odor only in both cold and hot water, If you are on well water and hVE no iron or manganese (rust, red or black staining) the best option is to use an Air Charger Carbon Filter with the peroxide cleaning kit.

If your well water smells like rotten eggs and you have iron in your water and rust staining,  install a chlorinator followed by an iron filter. An iron removal filter can remove low to moderate amounts (up to around 10 mg/l) of hydrogen sulfide in addition to removing iron and manganese. The filter oxidizes the hydrogen sulfide, converting it into insoluble sulfur which the filtering process then removes.


Do you have rotten egg or sulfur smells in your cold or hot water? Or would you like more help in learning how to treat sulfur odors in well water? Contact Aquatell today for more information.