Skip to main content
U.S. flag

An official website of the United States government

Taste and odor issues

Cyanobacteria and filamentous bacteria in the class Actinomyces can produce chemicals such as MIB and geosmin which are odorous chemicals that can impact drinking water. These chemicals are not harmful but are considered “nuisance” constituents in natural waters.

A photograph of petri dishes growing Actinomycetes colonies.
This photograph shows petri dishes inside an incubator that are growing Actinomycetes colonies. Actinomycetes are a group of bacteria with fungal-type morphology and are nuisance organisms in water and in the wastewater treatment process. Most Actinomycetes form chemicals that impart an earthy, musty odor to public water supplies.  
  • The OWML uses cultural methods to detect actinomycetes, a spore-forming bacteria that lives in soil and water and can produce chemicals that are common causes of earthy or musty drinking water odors.
  • The OWML can analyze for geosmin and MIB synthetase genes using qPCR: assays can target Cyanobacteria and/or Actinomyces.