What vent stack means
A vent stack is a vertical pipe that lets air into and out of the drain system, usually through the roof, so water drains smoothly and trap seals are not siphoned out.
Also called plumbing vent, stack vent, vent pipe.
Where it matters on a plumbing job
Gurgling drains and slow fixtures on one side of a house are often a blocked vent. Clearing a vent means a roof trip, so price it with ladder and roof access in mind. Roofers should never cap a vent during a reroof.
What the model code says
- The code defines a vent stack as a vertical vent pipe that circulates air to and from the drainage system through one or more stories. (IRC 2021, Chapter 2)
- Every plumbing system needs at least one stack vent or vent stack that reaches the open air outside. (IRC 2021, Chapter 31)
Check which code edition your building department enforces for vent stack before you quote.
What it costs
Koira's drain cleaning cost guide puts a typical job at $270, with most between $200 to $380. The guide shows its sources and what moves the price.
Work it out
- Cost guide: Drain cleaning cost
- Licensing: Plumbing license rules by state
- Tools, templates and guides: Free plumbing resources
Sources: 2021 International Residential Code, Chapter 2, Definitions (ICC); 2021 International Residential Code, Chapter 31, Vents (ICC). Checked October 9, 2026.