Microbial Indicator Testing in Potable Water Wells

Preliminary results of data compiled from bacteriological testing of potable water well samples received in our diagnostic water testing laboratory during a 5 year period will be presented. The well samples constitute a random sampling of mostly municipal wells that were in need of remediation and are distributed throughout the United States and Canada. This laboratory investigation was undertaken to determine what relationships exist between microbial indicators in potable water wells specifically, total coliform and E. coli bacteria, sulfate reducing bacteria, and protozoa. Over 15% of those potable water samples tested positive for total coliform, and 2% tested positive for E. coli. Of the samples that tested positive for total coliform, 65% also tested positive for sulfate reducing bacteria, and 85% of the positive E. coli tests resulted in positive sulfate reducing bacteria test results. Protozoa were found in over 25% of all potable water samples at greater than trace numbers. Further investigation of the data will show the microbial relationships within the potable well test group, and report the most common bacterial species associated with positive total coliform and E. coli tests.