Coliform bacteria can be found virtually everywhere - in soil, on skin and lakes and rivers. Generally, coliform bacteria do not cause disease but their presence in drinking water is an indication that more harmful organisms might also be there.

Total Coliform Rule

The Safe Drinking Water Act's Total Coliform Rule deals with the detection of bacterial contamination in drinking water. The federal rule, which applies to all public water systems, allows up to 5% positive tests for coliform bacteria in a given month. In the District, the treatment and testing of drinking water is done by the U.S. Army Corps of Engineers' Washington Aqueduct.

The regulation provides this 5% window for positive tests in recognition of the limitations of bacteriological testing and the possibility of contamination of samples during collection and analysis. If a water sample tests positive for coliform bacteria, follow-up tests are conducted to help analysts determine whether a problem exists.

The Environmental Protection Agency also has declared that all drinking water samples must be free of a fecal coliform known as E. coli. The presence of any E. coli bacteria is an acute violation of the total coliform maximum contamination level. In November of 1995, E. coli was detected at one testing location in the District. A boil-water alert was declared for that neighborhood but subsequent tests revealed no E. coli and the alert was canceled the following day. Subsequent testing has never detected the presence of E. coli.

Since September of 1996, the DC Water and Sewer Authority has been well within all federal coliform limits.

What are the symptoms associated with waterborne diseases?

If someone has been infected by drinking water contaminated by disease-causing organisms, symptoms may include: diarrhea, cramps, nausea and possibly jaundice, headaches and fatigue. These symptoms however are not just associated with disease-causing organisms in drinking water, but also may be caused by a number of other factors such as the flu or even the common cold. The Federal Centers for Disease Control and Prevention recommend that you consult a physician if you experience diarrhea for a prolonged period of time.

What is DCWASA doing to ensure a continuous supply of safe drinking water?

The Authority is engaged in an ambitious $1.6 billion 10-year capital program that includes repairs and upgrades to its drinking water distribution system. All reservoirs have been cleaned and inspected, water mains are being flushed, pipes are being cleaned and relined, and a new EPA-approved drinking water sampling plan ensures timely and highly accurate testing.

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