Plumbing question; when I run the water in the shower, lavatory or kitchen sink, for 3 or 4 minutes or longer?

I hear a loud gurgling sound coming from the toilet. It does this often but not every time. What is causing this?

Public Comments

1. Perhaps the vent line is plugged. The running water is creating a vaccum in the drain line and pulling in air from the toilet. If you have access to the roof, perhaps you can check to make sure something hasn't covered up the vent pipe.
2. Have a plumber clean your vent lines!
3. You have a vent problem. If it worked ok before, you must have an obstruction somewhere.
4. Yep ,vent line!