The following sections describe procedures for examining a water sample’s microbiological content. These methods were developed primarily to permit rapid examination of water samples, so analysts often assume they only apply to routine examinations. However, they are suitable for both compliance monitoring and research studies of ambient, drinking, waste, and marine waters. The methods are used by many laboratories and are the best techniques currently available, but to be effective, their limitations must be thoroughly understood and appropriate quality control practices followed. Therefore, investigate all techniques to establish their specificity, improve their procedural details, and expand their uses in analyzing various types of water.
Routine bacteriological analyses do not provide a complete water quality picture. Always consider bacteriological results in light of the sanitary conditions in and around the sample source. Water quality evaluations based on test results of a single sample from a given source are inadequate. When possible, base water quality evaluations on the results of a series of samples collected and analyzed over a protracted period.