What must be tested before placing a main into service?

Before placing a water main into service, the primary requirement is to conduct a bacteriological sample test. This is critical because water quality directly impacts public health. The presence of harmful bacteria in the water supply can lead to serious health issues, including waterborne diseases. Therefore, it is essential to ensure that the water is safe to drink and free from contaminants before the main is officially put into use.

Bacteriological testing typically involves taking samples from the water and analyzing them for indicators of fecal contamination, such as coliform organisms. If the results are satisfactory and indicate that the water supply is safe, the water main can then proceed to be placed into service.

While pressure tests, chlorine residual checks, and flow tests are important components of the commissioning and maintenance processes for water systems, they primarily focus on ensuring the structural integrity of the pipeline, the effectiveness of disinfection, and the system's operational capability, respectively. However, these tests do not assess the microbiological safety of the water, which is why bacteriological sampling is prioritized before operational use.