The answer to 'why is my roof vent leaking' is that a roof vent can leak for several common reasons, including worn or damaged seals, improper installation, or damage to the vent itself. Symptoms of a leaking roof vent may include water stains around the vent, mold or mildew growth, and even dripping water inside the home.
Some of the most common causes of a leaking roof vent include dried, cracked, or missing seals and gaskets, loose or missing fasteners, damage to the vent housing or flashing, and improper installation. Resolving the issue may require re-sealing the vent, replacing damaged components, or in some cases, completely replacing the roof vent.