Coliform bacteria are groups of
bacteria that indicate the possible presence of infectious disease organisms.
The coliforms are a broad class of bacteria which live in the digestive tracts of humans and many animals. The
presence of coliform bacteria in tap water suggests that the treatment system is not working properly or that
there is a problem in the distribution system that moves treated water from the treatment plant to customer
Although many types of coliform bacteria are harmless, some can cause health problems which
include diarrhea, cramps, nausea and vomiting. Together these symptoms comprise a general category known as
gastroenteritis. Gastroenteritis is not usually serious for a healthy person, but it can lead to more serious
problems for people with weakened immune systems, such as the very young, elderly, or immuno-compromised.
It is recommended that water with coliform
bacteria not be consumed until the problem is resolved. Coliform bacteria may get into the water supply through
surface water run-off, especially after heavy rainfall. Fecal coliform, when accompanied by high nitrate and
sulfate levels, may indicate a septic system or other fecal pollution source.
Coliform bacteria present at a public water supply user's faucet may be a result of water and
sewage pipes being cross connected causing plumbing backflow. In the microbiological section of your WaterCheck report, you will
see a brief narrative indicating the presence or absence of coliform bacteria.
When elevated levels of this contaminant are
found in your water, consulting the local health department, a physician or a local water treatment specialist may
Be aware of activities in your community
that can put your drinking water at risk. Talk to your neighbors to determine if problems with your drinking water
are individual or community-wide. Check out he history of the area in which you live to determine if past
activities are having a present impact on your drinking water.
Testing for Coliform Bacteria:
National Testing Laboratories Corrective Action Brochure
U.S EPA Total Coliform Rule
Return from Coliform Bacteria to Water Quality and