Using a retrospective case-control study, we compared poolside tests with bacteriological samples during three consecutive summers. A total of 844 matched samples were obtained. Increased chlorine levels were associated with lower rates of contamination. Alkalinity, pH, and TDS were not statistically associated with bacteriological failures. In swimming pools with > 1 ppm of chlorine, 27/30 (90.0%) passed bacteriologic evaluation. In spas with < 1.0 ppm of chlorine, only 12/28 (42.9%) passed. Of the spas with > 3.0 ppm of chlorine, 170/176 (96.6%) passed. Of the wading pools with < 1ppm of chlorine, only 12/25 (48.0%) passed. Of the wading pools with > 2 ppm, 263/290 (90.7%) passed. Of available poolside tests, only chlorine levels are predictive of positive testing for fecal contamination. Higher levels of chlorine were associated with higher passing rates. Current standards for disinfection in spas and wading pools may need to be increased to help prevent contamination.