Toilet drain line size

[Jon mackay]

Is there a minimum size for a toilet waste line?

I came across a 3" cast iron line from a toilet and it just didn't look right.

[H.G. Watson, Sr.]

Why don't you go ahead and access the New York State Residential Codes?

[brian schmitt]

3" is the minimum size for A toilet.

[Jon mackay]

Why don't you go ahead and access the New York State Residential Codes?

Is there a link to that?

[Jon mackay]

This was a small commercial office that has a history of the toilet backing up. When I saw the 3" I just thought I would throw it to the forum as all the residential toilet lines I find are 4".

[Ron Hasil]

THe Picture is from the New York State Code. Look at the foot note (a.) it states the minimum size of any buidling drain serving a water closet shall be 3" Here is a link to the state plumbing code 2006 New York State Plumbing Code (http://www2.iccsafe.org/states/new_york/NY_Plumbing/plumbing_frameset.htm)