Why does my drain gurgle?

Gurgling drains happen when air is trapped in your plumbing pipes and bubbles up through water in the trap. This usually means there is a partial clog creating negative pressure or a venting issue. Start by checking if multiple drains gurgle at once, which suggests a main vent blockage. Try clearing individual drains with a plunger or snake. If the problem persists across multiple fixtures, a plumber may need to clear a blocked vent stack on your roof.