What Is Sulfate?

By Catherine M. Korenchan; Updated April 24, 2017

Occurring naturally in groundwater, high levels of sulfate can lead to temporary dehydration and laxative effects. If you are not used to drinking water that is high in sulfates, there are no serious health risks. Sulfate salts, however, are used for a variety of purposes--from reducing greenhouse gases to leaving a bad taste in drinking water.


Sulfate is an inorganic salt of sulfuric acid. The ion sulfate is a polyatomic anion with the empirical formula SO4. Many sulfate salts are highly soluble in water. Sulfates increase the acidity of the atmosphere, creating acid rain. The Twomey effect, or the effect of sulfate aerosols on cloud formation, may offset the warming effect of greenhouse gases and occurs largely downstream of highly industrial areas.


Soil and rock formations may naturally contain sulfates. As water moves through these, sulfates are picked up and dissolve in the groundwater, according to Minnesota’s Department of Health. Sulfur-oxidizing bacteria convert sulfides into sulfates and leave dark slime that blackens water and can stain the inside of toilet tanks. An article published by Wilkes University states that sulfur-reducing bacteria are more common than sulfur-oxidizing bacteria.

Common Uses

Sulfate salts have diverse applications. Magnesium sulfate, or Epsom salt, is used for therapeutic baths; gypsum--the mineral form of hydrated calcium sulfate--produces plaster; and sulfate ions are used in some cationic drugs, according to New World Encyclopedia. Other sulfates include glucosamine sulfate, used for treating arthritis; hydrazine sulfate, commonly used in treating cancer patients; and copper sulfate, a fungicide that controls bacterial and fungal diseases of crops.


Higher levels of sulfate that occur in well water have a bitter taste and can have laxative effects, warns the U.S. Environmental Protection Agency. Infants and travelers may be at risk of sulfate's laxative and dehydration effects because they’re not accustomed to the higher levels in our water. According to Minnesota’s Department of Health, high levels of sulfates may corrode copper pipes. As a precaution, the department warns that you should not use tap water containing sulfates when preparing infant formulas.


You may wish to dilute high sulfur water with lower sulfur water until you become adjusted, Minnesota’s Department of Health suggests. There are several treatments available for well water that will lower the sulfate levels, and testing for sulfate-reducing bacteria is highly recommended, states Wilkes University. Sulfate-reducing bacteria can be a sign of sewage pollution and may contain contaminants that cause disease. Using chlorine bleach when washing clothes in high sulfur water can leave clothing stains.

About the Author

Catherine Korenchan is an advocate for social justice and has earned her Associate of Art degree in Liberal Arts. She has also worked in the business and manufacturing industries for 17 years. Korenchan comes from a print journalism background and writes for several online sites including Associated Content.