This classroom/laboratory manual is for use by operators of drinking water plants who must analyze samples for residual chlorine and turbidity. It contains background information on both tests; e.g., Federal requirements for compliance on residual chlorine and turbidity, principles involved in the tests, and factors affecting test results. It also contains laboratory procedures for conducting the two tests. Reagent preparation and instrument care are included. Miscellaneous other items are in the manual: an agenda, if the manual is to be used in the presentation of a training course, a pre- and post-course test, and a copy of the Federal Register which relates to the measurement of residual chlorine and turbidity. For those who desire to present instruction in these two determinations, there is an associated Instructor's manual PB81-226946, titled as above.