Colisure presence-absence medium was compared with standard reference methods for detecting low numbers of total coliform bacteria and E. coli in drinking water when the bacteria were subjected to chlorine stress. When Colisure was compared with established reference methods to detect total coliforms in dilute, disinfected samples, Colisure yielded more positive results after 24, 28, and 48 h than lauryl tryptose broth (LTB) confirmed in bile green lactose broth after 48 h. Colisure also detected higher levels of chlorine-injured E. coli than LTB confirmed in EC medium with 4-methylumbelliferyl B-D-glucuronide (EC/MUG). The sensitivity and specificity of Colisure were also evaluated and were determined to be between 96 and 100 percent on nonchlorinated samples when positive and negative tests were verified. Includes 44 references, tables, figures.