Regulatory, political, and institutional barriers have prevented broader use of rapid, simple, and inexpensive microbiological tests for Escherichia coli. By permitting greater use of chromogenic microbiological methods for compliance requirements by trained and certified operators of smaller public water systems, the cost of compliance should remain the same or decrease than when using distant laboratories. In fact, the lower cost of such methods would allow more frequent testing. New microbial methods allow greater public health protection because they are more sensitive to smaller amounts of contaminants in addition to allowing faster turnaround times--which would allow faster notification to the public. This article describes the [...]