A series of water samples taken over a given period of time and weighted by flow rate. Composite samples of water that accumulate, store, examine, and weight over a long period of time are useful in delivering a legitimate indication of treatment plant performance. However, taking in and examining these composite samples is an exhausting, and costly process. As a result, most organizations in charge of regulating the composite sample process are given the task of conducting performance evaluations that precisely measure the performance of these systems in a systematized, consistent setting.