AWWA JAW3912

Persistently high coliform counts in a portion of the distribution system of the East Bay Municipal Utility District in Oakland, California were traced to a growth-supportive organic coating on the interior of a steel tank. A procedure has since been developed by the utility to test coatings for bacterial growth support potential before the material is applied to the interior of potable water reservoirs. Tests performed on a variety of coatings reveal that selecting a coating that does not support growth, does not impart taste and odor to the water, and does not contain excessive amounts of toxic solvents poses a difficulty for utility design engineers. Includes 2 references, table.