Repeat bacti samples must be collected within how many hours?

The requirement for repeat bacteriological (bacti) samples to be collected within 24 hours is based on the need to quickly assess the safety of drinking water following a potential contamination event, such as a positive test for coliform bacteria. When a sample indicates the presence of harmful microorganisms, immediate follow-up is essential to determine whether that result reflects a transient issue or an ongoing contamination problem.

Collecting repeat samples quickly allows for timely intervention to protect public health, including potential corrective actions to treat the water or issue boil advisories if necessary. The 24-hour timeframe strikes a balance between ensuring rapid response to potential threats while allowing time for logistics in collecting and processing the samples accurately. This standard underscores the importance of prompt action in water quality monitoring and public health protection.