What is the maximum percentage of bacteriological samples that can be positive before violating drinking water standards?

The correct answer is that a maximum of 5% of bacteriological samples can be positive before violating drinking water standards. This threshold is established by regulatory agencies to maintain public health and safety regarding drinking water quality. The 5% standard is particularly relevant for total coliform bacteria tests, which are used as indicators of potential contamination and the effectiveness of treatment processes in water systems.

Maintaining a limit of 5% ensures that any detected contamination is addressed promptly to prevent health risks associated with consuming contaminated water. A higher percentage of positive results would indicate a significant risk of pathogen presence, which could lead to waterborne illnesses. Adhering to this standard helps water suppliers uphold high quality and safety in the drinking water they provide to the community.

In contrast, options that suggest lower percentages, such as 1%, 2%, or even 10%, do not align with the established guidelines for acceptable bacteriological quality in drinking water, emphasizing the importance of the 5% threshold for operational compliance.