Where must repeat samples be taken in relation to the original sample?

Repeat samples are critical for verifying the accuracy of water quality testing and ensuring that any contamination is properly assessed. The correct practice is to collect repeat samples within the same plumbing system as the original sample, specifically within a defined range of connections to maintain representative results.

Sampling within 5 connections upstream and downstream of the original sample point allows for the assessment of water quality in the immediate area, helping to identify whether the detected problem is localized or if it might be affecting a broader section of the distribution system.

Sampling from any point in the system may not reflect the same conditions that existed at the original sampling site, diminishing the reliability of the results. Taking repeat samples specifically at the original tap or within the same geographic area, while helpful, does not provide as precise an assessment as the defined connection range does. Therefore, the requirement to take repeat samples within a specified distance from the original sampling point helps ensure that the results are both relevant and reliable.