A Homeowner's Guide To Drain Vents

17 February 2021
 Categories: , Blog


The plumbing system in your home consists of more than drain pipes and water lines. There is also an extensive ventilation system that runs from drains and certain fixtures to your roof. Issues with this vent system can affect your entire home.

Vent Location and Function

If you view your roof, you can see one or more pipes extending up from the surface. At least some of these pipes are plumbing vents. They connect to the main drain lines that run throughout your home, and some of them may connect more directly to certain fixtures like the toilet.

These vents serve an important purpose. Sewer gases can build up in both the secondary and main drain lines in your home. Gases can also come up your sewer line from the main municipal line. The vents allow a safe way for these gases to escape. Vents also ensure that the drains flow freely. Without a vent on a drain line, a vacuum will form, which prevents the wastewater from flowing outward. The vent provides a break in the seal so the drains work properly.

Common Vent Issues

Issues happen when a vent becomes damaged or blocked. Damage is often the result of storms or age. Wind, in particular, can break or twist a vent so that it no longer flows freely. Rain can also get into a vent with a damaged cap, leading to problems. Age typically affects old metal vents. They begin to rust and corrode, which leads to blockages in the pipe.

A blocked vent is most often caused by animal activity. Animals like squirrels or birds somehow gain access to the vent and block it with nesting materials. Insects may also block up a vent. They are drawn to the vent because the air coming out is warm, so blockage issues are more likely to occur in the winter and spring. Debris like leaves can also blow into and block the vent.

Repair and Damage Prevention

The first thing your plumber will do is inspect the vents. If the pipe itself is damaged, then you may need to have it replaced so that your system works properly. More likely, though, the damage will be to the vent cap.

The vent cap is designed to allow airflow and prevent debris or animals from blocking the vent. Your plumber may need to reattach the vent cap or install a new one, depending on the type of damage.

Contact a plumber in your area if you suspect a problem with the drain and plumbing vents on your home.