The answer to 'why is my pressure regulator making gurgling noise' is that the pressure regulator is likely not functioning properly and needs to be repaired or replaced. A gurgling noise from the pressure regulator is a common symptom of a problem, often indicating a blockage or malfunction in the internal components.
Some common causes of a gurgling pressure regulator include mineral buildup, a faulty diaphragm, or a worn-out spring. If the regulator is not regulating the water pressure correctly, it can create turbulence and the gurgling sound. In some cases, the regulator may need to be adjusted or cleaned, but a complete replacement may be required if the internal parts are severely damaged.