Minimum pipe size for a toilet vent?

According to my hand book the minimum pipe size required to vent a toilet is:

1.5â€

Or

2†as a wet vent for a sink.

Am I understanding this correct?

What code are you using? UPC requires 2" for a toilet vent.

Wet vent

Ok so I need at least a 2†vent for my toilet.

Can I also drain my sink into the same 2†pipe?

I still don't know what code you're using, or how you're going about it.

It depends on your location

It really depends on your local in the USA

I get away with murder in INDIANA with our code....

1 1/2 pvc is big enough for the whole house to be
vented onhere....


other parts of the country expect a full
3 inch stack out hte roof..

With newer toilets that flush faster, you would want at least 2" on the vent.

In some places you can wet vent a bathroom lav over a toilet, if that line is 2" or larger.
A kitchen sink could not be wet vented.

Herk said:

I still don't know what code you're using, .

Click to expand...

The book I am reading is a general construction book it covers everything from grading to roofing. The book dose not tell me specifically what size vent I will need for a toilet; however, it dose have tables soused from: "UBC Illustrated training manual (Walnut, calif: International association of plumbing and mechanical Officials 1985)."

In one table I read that a private toilet counts for 4 fixture units. The next table shows 1.5" pipe being capable of venting 8 fixture units. Based on these two tables it appeared that 1.5" pipe could actually vent 2 toilets.

In the houses I have worked on I always see 2" vent pipes for toilets, add to that your reaction and the fact that I don’t want to get into a challenge with my inspector, I am definitely not going to install a 1.5†vent on my toilet.

acording to UPC 2006

Thank you for the diagram Terry!

In some places you can wet vent a bathroom lav over a toilet, if that line is 2" or larger.

Click to expand...

So It is ok to use a 2" pipe as a wet vent for a toilet and a bathroom lav. Would this setup be in compliance with: "UPC 2006"?

It has been my experience that most cities in the LA basin don't make up plumbing codes; instead they simply adopt "UPC". But I will need to confirm it in my particular city.

I have the third edition of the code check plumbing for 2006, the little flip job books, it says the IRC does not require a vent on a water closet for residential. What's up with that?