Can PVC soil pipe be installed straight down with lines Td off to the main, or must it maintain the same angles as cast iron?
Asked by Asunción Medina 
7 months ago
Last Updated: May 9, 2024
So, when I switch out this cast iron soil pipe for PVC, can I just have it come straight down with the two lines branching off to the main? Or does it have to be at those particular angles?
Of course.
I disagree.
I don’t think you quite grasp the point of the post about plumbing, .
Has been involved in full house renovations for more than 20 years. He agrees there aren’t many details provided. You can descend directly to the main drain, but a T connection won’t suffice.
Confirmed it is a wall. Both pipes are vertically aligned.
Knows it’s a wall. That’s why I mentioned going down to the main drain. You still need an angle and wye for a connection, not a T.
That’s a cute picture. It’s important to note that if the pipes are running vertically on a wall, a person can use either a T or a Y. The fittings would be upright. If it’s on the floor, the T would be sideways as a drain and not permitted in either code book. You should grab a book and read it before criticizing those who know their stuff
Hey buddy, just be yourself. It’s strange that everyone else is saying one thing, except you. I have never had a failed job
I think I’m the only plumber who still reads books. Actually, both of them
So, you have a 45 and then a wye connecting to the main stack. It’s perfectly fine to incorporate a 90 further down the line, run horizontally for 2 feet, then switch back to a vertical direction using a tee. Make sure the horizontal section maintains a slope of about 1/2 inch. While it may not be an improvement from the current setup and could potentially pose slightly higher risks, it will meet code requirements and should still function properly
The flow of 45’s is smoother compared to 90’s
A great resource is to ask a plumber
Opt for a Y fitting over a T fitting for better results
When running the pipe vertically, be sure to include a wye fitting to avoid sewage from flowing in the wrong direction. Check out this link for more information and an example: http://www.ncwhomeinspections.com/Sanitary+Tees,+Wyes+and+Sanitary+Combos#:~:text=When%20connecting%20any%20vertical%20waste%20drop%20to%20a,%26%201%2F8%20bend%20already%20made%20in%20one%20fitting.
Make sure to use a Y to maintain consistent flow and prevent issues with clogs or reverse flow