How to Vent Basement Bathroom Plumbing

If you’re remodeling your basement bathroom, one of the first things you’ll need to do is venting. Venting allows the sewer gasses from your toilet to escape so that they don’t get trapped in your home. Here’s how to do it.


  1. Measure the distance between the floor joists and cut a length of pipe to fit snugly between them.


  1. Secure the pipe with a U-shaped clamp or tie it to the joists with a wire tie (it’s best if you can use multiple ties).


  1. Connect the pipe to an exterior wall by attaching it with another clamp or wire tie around one of the studs in the wall (you can also use screws). The pipe should be located above grade and at least 6 inches away from any other building materials such as drywall or insulation, which would prevent proper ventilation if they were too close together

How to vent plumbing in an old house

If you’re venting plumbing in an old house, it’s likely that you have a vent stack. If this is the case, then you’ll need to make sure that the stack is properly sized and in good working order.


If your existing stack is too small or obstructed, then it won’t be able to handle the volume of water that passes through it during normal use. This can lead to poor drainage and flooding in your basement and attic.


To check if your existing stack is large enough for normal use, measure its diameter (in inches) and multiply by two (2). Then compare this measurement against the minimum size requirements set by local codes:


  • Minimum diameter (in inches) = 1/2 x total area of drain lines
  • Minimum length (in feet) = 2 x total area of drain lines

Can you vent plumbing into the attic?

The short answer is no. You cannot vent plumbing into the attic. You should always use a dedicated vent to evacuate gases and moisture out of your home. This is especially important in areas with high humidity, like basements.


If you have an older home and have never done any remodeling, you may already have a dedicated vent for your bathroom or laundry room that goes out through the roof. If not, then you will need to install one before any plumbing work is done in those rooms.


There are two different types of vents: 90-degree and 45-degree. 45 degree vents are usually used for dryer exhaust systems, but they can work for bathroom or laundry room vents as well. They are also less expensive than 90 degree vents because they don’t require as much installation effort or materials.


90 degree vents are usually recommended for toilet exhaust systems because they provide better ventilation than 45 degree models do (although 45 degree units will still work fine if that’s what you’re working with). However, installing them requires more time and money than 45 degree models do because they require more pipe length between their vent terminations and the terminations on your roof (where they connect with other parts of your system).