The bacteria analysis for total coliform and E. coli is an enzyme substrate method called Colilert that is analogous to the commonly used multiple tube method. Bacteria counts are expressed as a most probable number (MPN) per 100 milliliters (mL). Three or four different dilutions are prepared for each site by adding an aliquot of sample to sterile, deionized/distilled (DI) water to produce 100 mL of liquid. A powdered reagent is added to each dilution bottle and the mixture added to a sterile, plastic tray containing 97 wells and incubated for 20 hours at 35 degrees Celsius. The wells produce a yellow color when total coliform bacteria are present and fluoresce under UV light when E. coli are present.