What results must a bacteriological sample show before a main is placed into service?

Before a water main is placed into service, it is crucial that the bacteriological sample shows negative results for coliform bacteria. This requirement is in place to ensure that the water supply is safe for public consumption and does not pose a health risk. Presence of coliform bacteria can indicate contamination and the potential for waterborne illnesses, thus negative results are essential to confirm that the water is free from harmful pathogens.

The negative result is significant because it reflects compliance with health and safety regulations that aim to protect the community from waterborne pathogens. This procedure is a standard practice before a new or repaired water line is activated, as it helps maintain water quality and public health.