What must be done before taking a distribution system sample?

Before taking a distribution system sample, it is essential to disinfect the sample point by torching or using chemicals. This step is crucial to prevent contamination of the sample, ensuring that the results accurately reflect the quality of the water in the distribution system. Disinfecting the sample point eliminates any potential pathogens or contaminants that may be present on the surface, thereby safeguarding the integrity of the sample and allowing for reliable testing results. This practice is a standard procedure in water treatment to maintain the scientific validity of the sampling process.

It is important to note that while flushing the sample point is a common practice to ensure representative samples, it is not sufficient on its own without prior disinfection. Calibration of the sampling equipment and checking the water temperature are also important steps in the overall sampling process, but they do not directly address the need to eliminate contamination from the sample point itself before obtaining the sample.