Which type of valves must be installed on water supply lines?

Shut-off valves play a critical role in plumbing systems by providing a means to stop the flow of water within the supply lines. They allow for maintenance and repairs to be conducted safely and without the need to drain the entire plumbing system. For instance, if a pipe bursts or a fitting needs replacing, the shut-off valve can be closed to isolate that section of the system. This ensures that water can be readily halted at specific points, making it essential for effective plumbing management.

In addition, shut-off valves are often required by plumbing codes at various locations in a system, such as at the water meter and in branch lines supplying major appliances like water heaters or washing machines. The installation of these valves contributes to safety and facilitates emergency situations where immediate action is needed to prevent damage from leaks or flooding.

Other types of valves, such as pressure relief valves, backflow prevention valves, and check valves, have specific functions that are important in certain contexts, like protecting from over-pressurization or preventing contamination of the supply line. However, the fundamental task of controlling the flow of water through installation points within the system is primarily associated with shut-off valves. Their presence is necessary to fulfill both practical and code requirements in plumbing systems.