1. Determine the location of the water shut-off valve The main water shut-off valve is usually in the basement or on an outside wall in a utility area of the house. It's noticed that this valve can be seen as the most important valve which allows water to flow through the pipe when it is opened. If homeowners find any serious leaking point or broken pipe, turning off this valve is the first step you need to do before calling a professional plumber. 2. Know how to use Plumber'