Rainfresh water test kits are simple, reliable and accurate do-it-yourself water quality tests that detect a variety of contaminants in the water. Rainfresh WC1 water check test kit is a presence/absence screening tool for detecting coliform and E-coli bacteria. It is sensitive enough to detect even 1 CFU/100 mL of water. The kit can provide a single water test. It includes plastic bag with a special growth medium. Sample water is simply added to the bag and mixed with the growth medium to form a straw yellow solution. The growth medium has been specifically designed for the preferential growth of coliform when incubated at a temperature of 35 to 37 deg C for 24 hrs. Under these conditions, coliform, if present, outgrow other bacterial species that may be present in the water sample. As the coliform grow, they are induced to secrete an enzyme that causes a color change of the solution to blue-green.