After recording the pressure drop in a main drain test, what is the next step?

The next step after recording the pressure drop in a main drain test is to close the main drain. This action is critical for several reasons. First, closing the main drain helps to stabilize the system after the test has been conducted, allowing you to accurately assess the system's static pressure and ensure no further water is leaving the system during the observation phase.

Moreover, closing the main drain prevents any potential backflow or contamination from entering the system after the test has been completed. This step is essential before moving on to the observation of final static pressure, as it allows for a controlled environment where the pressure can be accurately measured and recorded without interference. Therefore, closing the main drain is a vital part of maintaining the integrity of the system following a main drain test.