The answer to 'why is my drain making gurgling noise' is that it is likely a sign of a blockage or problem in your plumbing system. A gurgling drain is usually caused by air bubbles being forced up through the water in the drain, often due to a clog or other obstruction.
Some common causes of a gurgling drain include hair, soap scum, food particles, or other debris building up in the pipes. This can create a blockage that traps air, causing the gurgling sound. Other potential causes include a problem with the vent pipe, a malfunctioning P-trap, or issues with the main sewer line.