How many service connections downstream must be resampled if a micro test fails?

When a microbiological test fails, it indicates a potential issue with the water supply that may affect public health. To ensure safety, regulatory guidelines typically recommend resampling a certain number of service connections downstream from the test point.

The correct answer indicates that resampling should include five connections. This number is significant because it allows for a comprehensive assessment of the water quality in the distribution system. By checking multiple service connections, operators can determine whether the contamination is isolated or more widespread. Resampling just a single connection might overlook critical issues, while testing fewer than five could fail to provide a clear picture of the overall situation. This targeted approach helps to ensure that any necessary corrective measures can be identified and implemented effectively, safeguarding public health and confirming the safety of the drinking water supply.