Before major water treatment facilities are designed or built, pilot plant studies are often conducted. These studies need to be planned and carried out properly if they are to provide the desired benefits. Pilot plant studies may be conducted to evaluate treatment or operating alternatives, or to evaluate theories or concepts of operation and treatment. Data needs for pilot studies can include water quality data and cost data. An appropriate range of conditions, including extremes that may be expected, should be evaluated. Equipment used in pilot plants should be of an appropriate design, suitable for scale-up and reasonable to operate. Data collection should not be excessive, but documentation of methods and results must be adequate. Quality control and quality assurance are very important. Data from the project should be reviewed frequently to ascertain that the study is accomplishing the desired goals. After pilot operations are completed, final analysis of data and preparation of a clear, understandable report are the concluding tasks.