Coliform Bacteria in Drinking Water NONCOMMUNITY PUBLIC WATER SUPPLY PROGRAM Contamination of Drinking Water noncommunity public water systems, by Microorganisms however, more frequent testing is sometimes required. Water samples that Pathogenic (causing or capable of causing indicate the presence of coliforms triggers disease) microorganisms are among the the collection of additional samples to oldest threats to drinking water quality, and confirm the contamination. More sampling are responsible for most of the waterborne is required to ensure the contamination has diseases that occur worldwide. Although it been eliminated. is not a common occurrence in the United States, pathogenic microorganisms such as What Does It Mean When Coliform bacteria, viruses, and protozoa can Bacteria Are Found In My Water sometimes find their way into drinking water supplies and cause human illness. Coliform bacteria are not considered a normal inhabitant of groundwater or Role of Coliform Bacteria in disinfected surface water. Their presence Detecting Contamination suggests that there has been a breach, failure, or other change in the integrity of Not all disease-producing microorganisms the water system. Disease-causing present in water are known or easily microorganisms may also have gained entry identifiable. The best approach for into the water system. While coliform identifying microbiological contamination is bacteria themselves pose little health risk, the use of an easily measured “indicator their presence indicates that other health- organism” to signal that pathogenic threatening microorganisms may also be microorganisms may be present. The present. The presence of E. coli is a strong coliform group of bacteria is the indicator indicator of fecal (sewage) contamination. used for this purpose in testing drinking This type of contamination greatly increases water. They are found in water, soil and on the likelihood that other pathogenic vegetation, and are present in large microorganisms are present. numbers in the feces of warm blooded animals. They quickly and inexpensively give Safety of the Water Supply and an indication that other pathogenic Possible Health Effects microorganisms may be present. For example, some strains of Escherichia coli (E. Total coliform bacteria (without the coli) can cause serious illness, and are presence of E. coli) are generally not members of the coliform group. considered harmful, but their presence indicates a potential pathway for Coliform Bacteria Sampling contamination to enter the drinking water. If you have specific health concerns, you Minnesota Department of Health (or your may want to consider seeking an alternate local health department) typically samples source of water. for coliform bacteria on an annual basis at COLIFORM BACTERIA IN DRINKING WATER The presence of E. coli indicates pathogenic Food, Beverage and Lodging Establishments microorganisms may be present in your (https://www.health.state.mn.us/communiti drinking water and increases your risk of es/environment/food/docs/fs/fecalcol.pdf) contracting a waterborne illness. Therefore, a noncommunity public water supply, Common Causes of Coliform where the presence of E. coli bacteria has Bacteria Problems been confirmed, is not considered safe for There are many reasons why coliform drinking water use. bacteria may be found in a water supply. Symptoms of waterborne illness may include Some common causes include defects in the gastrointestinal cramps, diarrhea, nausea, water distribution system, problems with headaches, or other symptoms. It is the well, cross connections with nonpotable important to note that these symptoms may water, poorly maintained treatment be caused by other conditions. Some groups equipment, or failure to disinfect following of people, such as infants, young children, repairs or seasonal opening. In general, the and those with compromised immune presence of coliform bacteria most often systems may be more susceptible to indicates a problem with some part of the waterborne illness. well or distribution system. Public Notification Requirements Resolving the Problem If total coliform bacteria is confirmed at a Coliform bacteria can be eliminated through noncommunity public water system, the a well and/or distribution system water may be consumed. A consumer disinfection. The cause of the coliform notice is required to be posted. Total presence is often unknown, but if one is Coliform Bacteria Consumer Notice determined, it must be corrected prior to a (https://www.health.state.mn.us/communiti final disinfection. In addition, a public water es/environment/water/docs/ncom/tcconsu system should always disinfect following mer.pdf). If E. coli is present in the drinking repairs, additions to the water system, or water, it must not be used for drinking, food seasonal opening. Disinfection instructions preparation, making ice, brushing teeth, or are available at Well Disinfection manual dishwashing. Purchased bottled (https://www.health.state.mn.us/communiti water must be provided to all users of the es/environment/water/docs/wells/waterqua water supply for these purposes. In lity/disinfection.pdf) addition, precautions should be taken when After the disinfection has been completed, washing hands, bathing, and showering. the water system must be re-sampled to Public notifications are required to be ensure the coliform bacteria have been posted. E. coli Public Notification eliminated. (https://www.health.state.mn.us/communiti es/environment/water/docs/ncom/ecolipn. pdf) 2 COLIFORM BACTERIA IN DRINKING WATER Causes and Actions Causes of Coliform Problems Preventative/Corrective Actions Lack of proper maintenance on treatment units such as Follow best practices and the manufacturer’s carbon filters, sediment filters, water softeners, etc. requirements pertaining to operation, maintenance, cleaning/sanitizing, and repair. Plumbing repairs or additions without system Always disinfect water systems after plumbing repairs disinfection. or additions. Seasonal systems can have coliform introduced during Never leave any part of the plumbing system open to draining, startup, or anytime drained water lines are the environment. Always thoroughly flush the system not properly closed or capped in the fall. when opening. Disinfect the well and plumbing prior to opening and during shutdown. Dead ends in the plumbing system allow water to Remove all unnecessary plumbing dead ends. become stagnant and sediment to accumulate creating Routinely run water through seldom-used fixtures. conditions favorable for bacterial growth. They are Ensure that feed lines to fire, boiler, lawn sprinkler created when plumbing fixtures are removed or taken systems, pools/spas, etc. have proper backflow out of service and the associated water lines are left in prevention installed and maintained. place. Dead ends can also exist on water feed lines to fire and lawn sprinkler systems, boilers, heat exchangers, pools/spas, church baptisteries, and seasonal or seldom used fixtures. Water systems with very low water use are in effect Periodically flush the entire water system by lawn dead ends and may promote bacterial growth. sprinkling, outside hose, or other means. Damaged, loose fitting, or missing well caps/seals and Repair or replace with a well code compliant cap/seal electrical conduits. and electrical conduit. During pump replacement coliform may be introduced Prevent drop pipes and wiring from becoming soiled from the new pump or the drop pipe/wiring if set on during pump replacement. Disinfect the well and the ground. plumbing thoroughly after pump replacement. Wells located in pits/basements are prone to Hire a licensed well contractor to extend the well contamination when the pit/basement floods and casing at least 12 inches above ground level and fill in water enters the well via the cap or vent. the pit or replace the well. Well casing that terminates near or at the ground Hire a licensed well contractor to extend the well surface allows surface water to enter the well through casing at least 12 inches above the surrounding ground the well cap or vent. level which has been graded to divert water away from the casing Well casing could be damaged above and below the Wells located in areas where motorized traffic occurs ground surface when struck by a motorized vehicle should be protected by surrounding the casing with allowing contaminated water through the damaged rigid posts, large rocks, or fencing. Avoid locating new casing. wells near traffic areas. Minnesota Department of Health PO Box 64975 St. Paul, MN 55164-0975 651-201-4700 [email protected] www.health.state.mn.us RV 06/01/2018 To obtain this information in a different format, call: 651-210-4700. Printed on recycled paper. 3 .