I have some a question on plumbing code relating to a vent stack modification in a shower/bathroom remodel on the ground floor of a Texas home (cement slab, no basement, pictures attached). This remodel will convert what was a small (and badly leaking) shower (3'x3') to a larger, walk-in one, move the shower drain to the center of the larger area (3'x6'), and relocate the h/c water lines and shower assembly to a rebuilt near wall on the other side of the shower. To summarize what I've done so far: The original framing enclosed the vent stack in a wall recess between the shower and the garage. I've replaced this framing, and used the recess to expand the shower area (pictures 1, 2, and 3): I've built new framing to contain all the new shower plumbing as well as the vent stack that serves the toilet. I removed the original near wall and rebuilt it using 2x8 lumber so that I could fit 3 inch PVC (3.5 inch OD, 4.0 inch OD at flanges) without violating any building codes (4.0/7.25 < 60% stud width), and to avoid any interference between the vent stack flanges with backerboard, sheetrock, etc. I also changed the path of the vent stack with two 90 degree bends to keep the PVC and clean-out access close to the garage wall, and to keep it from interfering with the shower valve rough-out and water lines (pictures 4 and 5): My questions: 1. Does this dogleg (pictures 4 and 5) at the clean out put me in violation of any plumbing codes? I've read elsewhere that there is a minimum height (6 inches?) for lateral transitions above any overflow associated with the waste line being vented, and transitions below this minimum need to be made via 45 degree bends at most. The vent stack line immediately serves the sewer line from the toilet. Should I reroute these elbows farther up in the wall? 2. Does anyone see a problem with with framing itself -- two neighboring 2x8 studs penetrated by 4 inch diameter holes? Sorry for the lengthy post, hoping someone has seen this sort of thing before. Thanks in advance.