Define - Bacteria in Drinking Water

Drinking Water Pathogens and Their Indicators: A Reference Resource
Disinfection byproducts are formed when disinfectants used in a water treatment react with bromide or natural organic matter (i.e., decaying vegetation) present in the source water. Different disinfectants produce different types and/or amounts of disinfection byproducts. Regulations are currently being implemented or are scheduled to be implemented for the following disinfection byproducts: trihalomethanes, haloacetic acids, bromate, and chlorite. 

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Pathogens are microbes that cause disease. They include a few types of bacteria, viruses, protozoa, and other organisms. Some pathogens are often found in water, frequently as a result of fecal matter from sewage discharges, leaking septic tanks, and runoff from animal feedlots into bodies of water. 

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Total Coliforms are a group of closely related, mostly harmless bacteria that live in soil and water as well as the gut of animals. The extent to which total coliforms are present in the source water can indicate the general quality of that water and the likelihood that the water is fecally contaminated. Total coliforms are currently controlled in drinking water regulations (i.e., Total Coliform Rule) because their presence above the standard indicates problems in treatment or in the distribution system. EPA requires all public water systems to monitor for total coliforms in distribution systems. If total coliforms are found, then the public water system must further analyze that total coliform-positive sample to determine if specific types of coliforms (i.e., fecal coliforms or E. coli) are present. EPA is increasing protection from pathogens in surface water systems as part of the Interim Enhanced Surface Water Treatment Rule, which becomes effective in December 2001. More information about E. coli 

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Cryptosporidium is a single-celled microbe contained in a group generally known as protozoa. Cryptosporidium may cause a disease, cryptosporidiosis, when ingested. Cryptosporidiosis symptoms can range from mild stomach upset to life threatening disease in those who are immunocompromised (e.g., people with severely compromised immune systems). Oocysts are a stage in the life-cycle of some Cryptosporidium. In this stage, the Cryptosporidium can infect humans and other animals. EPA regulates Cryptosporidium in drinking water, through the new Interim Enhanced Surface Water Treatment Rule, by requiring filtered surface water systems serving at least 10,000 to physically remove at least 99% of Cryptosporidium. Systems without filtration must adopt a watershed control program to protect the source water from Cryptosporidium contamination. This requirement becomes effective in December 2001. The effectiveness of treatment technologies are used to judge how well removal works since direct measurement of pathogens in treated water is not feasible. Additional Cryptosporidium information is also available from EPA's Office of Ground Water and Drinking Water. 

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Giardia lamblia (commonly referred to as Giardia) are single-celled microbes contained in a group known as protozoa. When ingested, they can cause a gastrointestinal disease called giardiasis. Giardiasis is a frequent cause of diarrhea. Symptoms may include diarrhea, fatigue, and cramps. Waterborne giardiasis may occur as a result of disinfection problems or inadequate filtration procedures. Cysts are a stage in the life-cycle of some Giardia. In this stage, the Giardia can infect humans and other animals. EPA regulates Giardia in drinking water by requiring water systems that use surface water or ground water under the direct influence of surface water to disinfect and/or filter their water so that at least 99.9% of Giardia are rendered harmless or physically removed. The effectiveness of treatment technologies are used to judge how well removal works since direct measurement of pathogens in treated water is not feasible. 

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Protozoa are microscopic, usually single-celled microbes which live in water and are relatively large in comparison to other microbes. Protozoa eat bacteria, and many are parasitic. 

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Viruses, including hepatitis A virus, rotaviruses, and Norwalk and other caliciviruses, are microbes that can cause illness. EPA regulates viruses in drinking water by requiring water systems that use surface water (or ground water under the direct influence of surface water) to treat their water to ensure that 99.99% of viruses are rendered harmless or physically removed. 

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Oocysts (cysts) are a stage in the life-cycle of some protozoa. 



Cryptosporidium Information 
Pathogen Information 
Pathogen Health Effects 
Drinking Water and Health 

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