Before collecting a sample, what is the recommended procedure?

Flushing sample lines before collecting a sample is a crucial step in ensuring the accuracy and reliability of the sample being obtained. This procedure helps to remove any stagnant water and contaminants that might have accumulated in the sample lines since the last collection. By flushing the lines, you help ensure that the water being sampled is representative of the system's current state, thus reducing the risk of obtaining misleading results due to previous residues or deposits.

This practice is standard in sampling protocols across various types of water and wastewater operations, as it enhances the integrity of the sample by allowing fresh water to flow through the lines immediately prior to collection. This step is especially important in wastewater sampling, where the characteristics of the flow can change rapidly, and maintaining sample integrity is vital for analysis.