Photo Credit: Becky Schuerman

Odors that are comparable to that of rotten eggs are not ideal in your home or coming from your drinking water faucet. Sulfate, which is a combination of sulfur and oxygen, are naturally occurring minerals. They are found in some soil and rock formations where groundwater is stored. Bacteria that feed on sulfur can produce hydrogen sulfide gas which is the primary offender when it comes to odor. 

Sulfate and hydrogen sulfide gas in drinking water are generally considered “nuisance contaminants” meaning, they do not pose serious risks to human health, but are aesthetically displeasing.

Sulfate is considered a secondary contaminant in the Environmental Protection Agency’s (EPA) current drinking water standards. Elevated concentrations of sulfate above 250ppm can impart a bitter taste, cause dehydration (especially in small children), or act as a mild laxative. However, most often people become acclimated to those levels and any issues tend to be minimized. 

Hydrogen sulfide is not currently considered a primary or secondary drinking water contaminant by the EPA. Elevated concentrations above 0.5ppm emits the rotten egg odor and at extremely high concentrations can cause people to become light headed if they are exposed to the gas for extended periods of time in a small confined area (i.e. a shower). However those instances are extremely rare. Additionally, elevated concentrations may also corrode metal plumbing and fixtures, and alter the taste and appearance of beverages and cooked foods. Occasionally the odor can actually come from a hot water heater if the magnesium corrosion control rod found in many hot water heaters interacts with sulfates in the water to form hydrogen sulfide gas.

Perhaps the largest challenge with these nuisance elements for the majority of people are that they can cause black sludge to form in pipes, water softeners and water fixtures in your home. This can also result in stains on clothes or other light colored linens in your home.

If you suspect you may have sulfate or hydrogen sulfide in your private water supply, the first step is to request a sample kit from an accredited laboratory and submit a water sample for testing to determine the concentration of both elements in your water supply. 

Treatment options for each contaminant are a bit different. To address naturally occurring sulfates, use point-of-use distillation or reverse osmosis. If the sulfate concentrations are very high, a whole house ion exchange system that removes iron and manganese along with hardness may be appropriate. For hydrogen sulfide issues, if the smell comes when using hot water, replacing the water heater’s magnesium rod should be considered.  Other forms of treatment for hydrogen sulfide include: distillation, reverse osmosis, granular activated carbon filtration that is designated for treating hydrogen sulfide, oxidizing filters and de-aeration.

It is important to remember that a treatment system is only as good as it is maintained. Filtration replacement intervals should be determined based on the contaminant(s) being removed and daily water flow through the filter. If you are not comfortable doing this yourself, contact a reputable water quality company in your area about your treatment equipment needs and if a maintenance contract is an option.

*Some of the information in this article came from former Extension Educator, Meghan Sittler.

 For further information on sulfates and hydrogen sulfide, each of the treatment options listed above and water testing, go to: https://water.unl.edu/article/drinking-water/nebguides.