Pathogens are microbes such as bacteria, viruses, and protozoa that cause disease. Pathogens may enter sources of drinking water from fecal matter in sewage treatment plant discharges, leaking septic systems, and storm water runoff from animal feedlots and other areas.

The protozoa, Cryptosporidium (“crypto”) may be found in drinking water and recreational water in every region of the U.S. and throughout the world. Crypto was identified as a contaminant of concern in all of the Source Water Assessments of the Washington, D.C., metropolitan area water suppliers. Cryptosporidium oocysts (infectious stage of the organism) are resistant to disinfection by chlorination and cause severe diarrhea in healthy individuals –and potentially life-threatening problems for people with compromised immune systems. The Partnership is investigating improvements in sampling, detection, and control of Crypto in the Potomac River basin.

Pathogen concerns are mainly handled through the Partnership’s Agricultural Issues workgroup, but are also considered in the Urban Issues workgroup.