A permit is not required for _____.

The correct choice highlights that a permit is not required for the repair of leaks in pipes, valves, or fixtures. This is because leak repairs are typically considered routine maintenance rather than alterations that would modify the overall plumbing system or its capacity. Permits are generally required for work that involves significant changes to plumbing structures, such as relocating fixtures, altering existing lines, or installing new systems—which could impact building safety and code compliance.

In contrast, activities like the replacement of a water heater, rearranging valves or pipes, and replacing a concealed vent pipe involve more substantial changes to the plumbing system. These types of work can affect the system’s overall integrity and functionality, thus requiring a permit to ensure that the modifications meet the necessary building codes and safety standards.