Abstract: A system for rapidly determining the presence or quantity of coliform bacteria in a water sample using the enzymes ?-D-galactosidase and ?-D-glucuronidase. The system includes a first filter means for separating bacteria from the sample and a broth for culturing the bacteria including an inducing agent for inducing enzyme production. A second filter means is used to separate the cultured bacteria from the broth. A lysing agent is exposed to the bacteria on the second filter and incubated with a chemiluminogenic substrate of the enzyme to produce a chemiluminescent product. Light emission is initiated from the second filter means and the emitted light is detected or measured directly from the second filter means using a luminometer adapted to receive the second filter means.