Course: BFM 203 Water Treatment and Control

Lecture

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The Importance of Sampling

Sampling is a vital part of studying the quality of water in the treatment process, distribution system, and source water. Proper sampling procedures are essential in order to obtain an accurate description of the water being sampled or tested. The primary source of error in the process of gathering water quality information often occurs during sampling. Sample selection, collection, and analysis must be representative of the water source or process you wish to examine. In other words, representative samples must be collected in order for test results to have any significant meaning. Samples must reflect actual water conditions.

The grab sample is a single sample collected at a particular time and place. The composite sample is a collection of individual samples obtained at regular intervals. Each sample is combined with the others in proportion based on flow or time. The combined sample represents average conditions during the sampling period. First draw samples are taken in accordance with the Lead and Copper rule after water has stood motionless in a customer's service line for at least six hours.