Signs of Poorly Vented Plumbing Drain Lines | Family Handyman

Have you ever wondered why is my toilet bubbling? If you have air bubbles that rise up through your toilet bowl (except when it flushes) or notice the water level rising and falling, you probably have a clogged or improperly vented toilet. This toilet bubbling problem is especially true when you have an appliance like a clothes washer nearby. Your drain plumbing line is gasping for air.