how to prevent rough in toilet and shower drains from not being plumb?

[mjricha]

I don't know exactly how to word this, so it is hard to search for an answer. I have looked all over and can't seem to find an answer.

I am roughing in a master bath on a slab. I will be using 4" pvc for the toilet and 2" for the shower drain. the sink will drain into the main stack.

there is very little give to 4" pvc, so when I am setting the slope in the ground under the slab, common sense (I think?) would tell me that since I am using a long sweep 90, the vertical pipe to the flange would be out of plumb to the same degree as the underground slope. Is there a trick to prevent this? this would go for the shower drain slope as well. I'm sorry if my question is confusing, I drew a picture to help me explain. Thanks for any help!

 

[CT18]

You can always cut the pipe flush with the floor and use an inside flange

 

[johnjh2o]

DWV 1/4 bends are not true 90's to allow for the pitch.

 

[Matt30]

Level your fittings. Grade your pipe

 

[mjricha]

DWV 1/4 bends are not true 90's to allow for the pitch.

Thank you very much! This is exactly what I wanted to know.