Water Distribution Grade 1 Certification Practice Exam

What does a positive bacteriological sample indicate?

1. Clear water quality

2. Absence of contaminants

3. Presence of bacteriological contamination

4. Low pathogen levels

The correct answer is: Presence of bacteriological contamination

A positive bacteriological sample indicates the presence of bacteriological contamination in the water. This means that tests have detected bacteria in the water supply, which could pose health risks to consumers if harmful pathogens are present. In water quality monitoring, bacteriological tests often focus on indicator organisms, such as coliform bacteria, which suggest the potential presence of pathogenic microorganisms. These tests are critical in assessing the safety of drinking water. The other options do not accurately reflect what a positive bacteriological sample represents. Clear water quality does not necessarily indicate safety, as the absence of visible contaminants does not guarantee that harmful bacteria are not present. Similarly, a positive sample specifically indicates contamination rather than an absence of contaminants or low pathogen levels. Thus, recognizing the meaning of a positive bacteriological sample is crucial for maintaining water safety and protecting public health.