What is a hydrostatic test used for in plumbing?

A hydrostatic test is primarily used in plumbing to check the integrity of pipes. This testing method involves filling the plumbing system with water and then applying pressure to ensure that there are no leaks or weaknesses in the piping. By monitoring the pressure over a certain period, plumbers can identify if there are any issues, such as cracks or defective joints, that could lead to system failures. This test is particularly crucial for new installations or after repairs to ensure that the system can handle the expected operational pressures.

In contrast, the other options pertain to different assessments. Determining water hardness involves testing the mineral content of water, measuring flow rate pertains to the efficiency of water movement within the system, and inspecting insulation relates to evaluating the thermal resistance around pipes rather than the pipes' structural integrity. Therefore, the hydrostatic test uniquely serves to ensure that the pipes themselves are secure and functioning properly without leaks.