To maintain system performance, the correct order of procedures for a new main installation includes what action last?

The final action in the process of a new main installation is to collect the bacteriological (bacti) sample. This step is crucial because it ensures that the water supply is safe for consumption after undergoing various treatments. Prior to sampling, the new main must be subjected to a series of preparatory actions: disinfection, flushing, and pressure testing.

Disinfection is performed to eliminate any harmful pathogens that may have entered the pipe during installation. Following disinfection, flushing is necessary to remove residual chlorine and any debris from the pipe, ensuring that the water in the new main is clean and clear. The pressure test checks the integrity of the system and ensures there are no leaks.

Once these steps have been completed, taking a bacti sample is essential to verify that the water is microbiologically safe. Testing at this stage provides assurance that the water quality meets health standards before the system is put into service.