Enter the (often called a vent stack). It’s a vertical pipe that runs from your plumbing system up through your roof. Its job isn't to carry water—it’s to carry air and sewer gases .

When a sink drains slowly or a toilet gurgles, most homeowners immediately reach for a plunger or a chemical drain cleaner. But what if the problem isn't below the floor... but above the roof?

Before you tear apart a perfectly good drain pipe, look up. The source of your plumbing nightmare might be sitting right on top of your house.