USGS Ohio Water Science Center
The OWML provides water-quality data on three major groups of microorganisms of public-health significance in the United States— protozoa, bacteria, viruses.
Surface water, ground water, and sediments are collected and analyzed for these microorganisms. For sample-collection methods for water and sediment and for special processing steps for sediments, refer to the USGS National Field Manual.
Because pathogenic (disease-causing) microorganisms may appear intermittently and in low concentrations and methods to detect pathogens are often costly and time consuming, bacterial and viral indicator organisms are often used to assess the microbiological quality of water. Indicator organisms are present in the feces of warmblooded animals and provide information on the possible presence of pathogens.
Find out more about the analytical methods used by the OWML for indicators and pathogens.