Confusing Basement Rough-in for Toilet

[no_regrets]

Rough-in for future toilet for bathroom in basement consists of 3” PVC nested inside 4” PVC. WTH? House built in 1997. The 3” pipe is too low for 3” flange, but high enough to block 4” flange. Can I just cut the 3” as low as possible (above weld) and use 4” toilet flange? Was this typical or someone’s bad idea on the spot and lacking correct parts?

 

[breplum]

NOT typical, nor does it make sense. idiots! wtf

 

[CT18]

A lot of times they use the bigger pipe so the concrete doesn't go tight against the 3" so the flange can sit down over the pipe and below concrete. They forgot to remove as they were pouring the floor

 

[GReynolds929]

The 3" is your drain and what the flange needs to connect to. If it's too short you'll need to extend it with either a coupling; or cut off the pipe, ream the hub, and add new correct length of pipe.