Are Toilets Vented (How It Works and Potential Problems)

Did you know that your toilet is vented? A vent helps ensure smooth movement of waste in under your home. If the vent doesn’t exist, or if it is clogged, it can cause a toilet to flush slowly, gurgle, and perform poorly.

If you take a look at your roof, you’ll see a number of vent pipes. Most homeowners understand there will be vents or fans above the stove and in the bathroom that help reduce smoke, hot air, and humidity.

But most of us don’t realize there are also vents connected to our toilets, sinks, and baths. The vent uses a thin pipe hidden in our wall, usually behind our toilet and sink. We don’t realize it’s there until something goes wrong.

Sometimes the toilet stops flushing properly and sometimes there are air bubbles entering the toilet bowl. In this article, I’ll share a information about the toilet vent, why it’s important, and signs on a vent clog.

Vented Toilets and Building Codes

If your toilet was installed more than 30 years ago, there’s a chance it doesn’t have a vent pipe. You can look at the blueprints of the house or ask a professional to learn if you toilet has a vent (more ways to find out if your toilet is vented).

If not, it would be wise to look into upgrading your plumbing with the help of a professional.

These days, housing building codes set minimum requirements for all structures, including plumbing and electrical.

In regards to plumbing, the basic concept is easy to understand. Pipes under our house transport grey water and waste to municipal sewage lines.

Our homes don’t use pumps to get waste to the sewage line. Instead, the process relies on neutral air pressure to allow waste to flow effortlessly through our pipes. Vents help ensure the air pressure is correct but vents also help with a number of other issues.

  • Quick movement of waste
  • Carries smell outside the house
  • Allows methane gas to safely escape the pipes
  • Removes air bubbles

Toilets will flush waste into the soil stack, which is a vertical pipe that feeds into the sewage line. The soil stack needs to be within 6 feet of the toilets and measures 3-4 inches in diameter but is often tapered to 2-3 inches as it is extended through the roof.

Are toilets vented - building code

The vent that extents from the soil stack allows waste to easily move into the sewage line under the house. A 1.5 inch vent works fine for a toilet, however, it’s easier to combine the sink and toilet vents if they are near each other. If you combine the vents the diameter of the vent should be larger (likely 2”).

In addition, sinks and toilet have different distance requirements from the vent (e.g. 5 feet or 10 feet and sink must be a continuous vent) so make sure you’ll following the building code specific to your State.

Is Your Toilet’s Vent Working Properly?

Most toilet clogs will have to do with the drain and will be easy to fix with a plunger or toilet auger (check my article on how to unclog a toilet). A vent clog will show a few unique signs. Here are a few signs of a vent clog:

  • Toilet gurgles or burps after flushing
  • Weak or slow flush
  • Smell coming from clean bowl

How to vent clogs or obstructions occur?

  • Leaves and woody debris from the roof
  • Household pests that fall into the vent (rats, mice etc.)

If you’ve tried unsuccessfully to get rid of a toilet clog, it might be time to check the vent.

Can I fix a toilet obstruction myself?

Unfortunately checking the vent isn’t easy and it’s a challenge to clear.

Vents are hidden behind walls and covered on the roof. A plumber will have tools to look inside the vent before opening walls.

>> check out the top reasons you need a plumber

In the best case, the plumber will be able to solve the problem without major work on the plumbing or wall. In the worst case, the plumber will need to cut into the wall and remove pipes to clean.

Conclusion

If your toilet was installed in the last 30 years it definitely uses a vent. Most people, however, don’t realize that toilets use a vent. If you’re unsure whether your house has one, go outside and look on the roof above the bathroom. If you see a covered pipe sticking up from the roof, it’s likely a vent.

A vent has a number of roles for our plumbing. First, it provides neutral air pressure in the drains. This allows waste and grey water to flow smoothly.

Second, it allows methane gas and smells to exit the pipes. Gas and smell can be unhealthy to breathe inside our homes.

Third, the vent removes the burps and gurgling sounds that are heard without a vent.

Toilets with vent problems usually come from obstructions. They will flush slowly, have air bubbles or gurgling and appear clogged.

If you’ve unsuccessfully tried all the conventional methods to remove a clog (plungers and augers), it might be due to something in your vent. Tree leaves, twigs, and rodents will occasionally become lodged in a vent and affect how the toilet works.

If you suspect something is clogging your vent, it’s best to call a plumber. Hopefully they can avoid cutting in the wall and look inside the vent from the roof.

A plumber will cost you, but it could save money in the long run if it can be fixed with minimal wall disturbance.

Thanks for reading another Toilet Travels article. Search our homepage for more helpful toilet articles and information.