Which component in a plumbing system regulates the flow of water to fixtures?

In a plumbing system, valves play a crucial role in regulating the flow of water to various fixtures. They are mechanical devices designed to open or close pathways for water, controlling its movement throughout the system. By adjusting a valve, a plumber can increase or decrease the flow of water as needed, effectively managing water supply to sinks, toilets, showers, and other fixtures.

Pipes serve as conduits to transport water but do not have the capability to regulate its flow. Faucets, while they do allow for the control of water flow at the point of use, are more specific components that rely on the presence of valves within the system. Connectors merely join different sections of plumbing and do not influence flow regulation. Therefore, the primary function of regulating water flow directly corresponds to the use of valves in a plumbing setup, making this the correct answer.