Understanding the Distinctions: Stopcocks vs. Stop Valves in Plumbing In the realm of plumbing, the terms "stopcock" and "stop valve" are often used interchangeably, yet they refer to distinct types of valves that serve different purposes. The primary function of a stopcock is to control the flow of water in a pipe, typically used in domestic settings. It is a simple, manual valve that can be turned on or off to stop the water supply. https://www.taishenghy.com/news/industry-news/what-is-the-difference-between-an-angle-valve-and-a-stop-valve.html