How to Vent a Toilet, Sink, and Shower | How to Vent a Shower Drain

How to Vent a Toilet, Sink, Shower

If you're adding a new bathroom to the unfinished part of your home, there is a good chance the plumbing isn't set up for it. What does that mean for you? It means you need to know how to vent a toilet, sink, and shower yourself. Or you need to hire someone to do it for you. One purpose of this blog post is to help you determine if you can handle this job and if you'd prefer to do it yourself.

We have all the info you need to get off on the right foot, including helpful graphics. We also have all the bathroom sinks, toilets, tubs and showers, and plumbing supplies you need to complete your home improvement project. Before we get to the project, let's go over a few basics.

What Is a Plumbing Vent?

All plumbing fixtures with a trap need venting, and without proper venting, the plumbing won't perform well. You'll hear horrible gurgling sounds when you flush the toilet. The vent is a pipe that connects horizontal drain lines to the exterior air above. As waste moves through the line, the air is drawn in through the vent for smoother passage.

Toilet Vent Pipe Size?

It's typically recommended that you go with a 2" PVC pipe for the vent. This is according to the uniform plumbing code (UPC). It may not be enough, depending on how many fixtures you are trying to run off the vent. You should check with local building code requirements to be on the safe side. Take note that the international plumbing code recommends just 1.5".

Toilet Vent Distance

According to the UPC, the distance between your trap and the vent should be no more than 6 feet. In other words, for the vent to work properly, it needs to feed into the drain line within 6 feet of the trapways that connect to it.

Plumbing the Bathroom

There are many different ways to vent your fixtures, and you're going to want to cater to the factors present in your bathroom. The most common configuration is to feed 2" PVC down from the ceiling within the wall behind the toilet. The vent pipe connects into the toilet drain pipe. The sink drain pipe and the tub/shower drain pipe are vented with 1.5"  pipe that branches off from the 2" PVC mainline.

To complete this project you're going to need PVC pipe, as well as DWV fittings and pipe. So let's get on with it. Here is a sample configuration:

infographic depicting how to vent toilet shower and sink

Example 1 (Pictured Above)

Through the floor, the toilet connects to the flange. The toilet flange connects to a 4" x 3" DWV closet bend, which then connects to a 3" combo (which looks more like a sanitary tee in the image, that's a little artistic error) which is also bringing in the air from the roof. The combo connects to a short run of DWV pipe which connects to a 3" x 3" x 3" wye.

To the right we see the sink connects with a trap adapter to the sanitary tee, which is bringing in air from the main vent line. A small run of DWV connects the tee to a wye combo with a cleanout cap sealing the open end.

To the left we see the tub drain connecting with a P-trap to the sanitary tee, which is also bringing in air from the main vent line. Then with a tiny run of DWV, the tee connects to the wye combo.

The discharge end of the wye connects to the building drain.

Shop PlumbersStock for Parts and More

Now that you know how to replace a toilet handle remember, you can save big on all the toilet parts and plumbing tools for this project at PlumbersStock. Our organization has over three decades of experience in the plumbing industry, and we've brought that expertise online. We are partnered with trusted brands, and we offer great prices. Industry professionals should consider doing long term business with us because we can deliver on hard to find parts and unbeatable deals. If you can buy in bulk, we can give you discounts so great that we can't advertise them, so please contact us.

Shopper Award