The answer to 'why is my shut-off valve making gurgling noise' is that the valve may be malfunctioning or there could be a blockage in the plumbing system. A gurgling sound from a shut-off valve often indicates that air is being drawn into the water line, which can happen when the valve is not sealing properly or if there is a clog downstream.
Some common causes of a gurgling shut-off valve include mineral buildup, corrosion, or physical damage to the valve itself. This can prevent the valve from closing tightly and allow air to be pulled into the system, creating the gurgling sound. In some cases, the gurgling may also be a sign of a larger plumbing issue, such as a leak or a blockage further down the line.