How to vent a relocated plumbing sink or drain
Moving a sink or bathroom fixture requires connecting to a main stack and navigating strict building codes that dictate where pipes can be routed. When constraints like exterior walls or existing basement layouts prevent standard connections, homeowners get stuck unable to safely move their plumbing.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
How to vent a relocated plumbing sink or drain
- 1Using a cheater vent instead of running a traditional vent stackDid this help you?
- 2Rerouting lines through interior wallsDid this help you?
- 3Reaching out to local plumbers for professional bids and adviceDid this help you?
- 4Cutting up the concrete slab and repiping undergroundDid this help you?
- 5Leaving the vent in its current configurationDid this help you?
- 6Consulting manufacturer installation manuals (RTFM)Did this help you?
- 7Hiring an engineer to calculate specsDid this help you?
- 8Changing the rough-in size to 10 inches and purchasing a new toiletDid this help you?
- 9Installing an offset toilet flangeDid this help you?
- 10Installing a sister joist against the existing one to cut into itDid this help you?
- 11Eliminating wall shimming to avoid joist interferenceDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Ideally we would also shift this main stack over to either be encased in a future wall, or at least much closer to the wall to open up the bathroom more.”source ↗
“Being that this is jn the basement and the main drain for the 2 bathrooms above it, I'm not sure if code allows this to be moved”source ↗
“I’m currently renovating my bathroom, which includes relocating a toilet flange. I’m only moving it over (along a floor joist) by about 2 feet so I didn’t expect a problem. However, I realized that I’ll need to also move the flange in towards (and hitting) the nearby joist by about 1.5.””source ↗
“My question is - what do you all think would be my best move? Here’s the options I’ve come up with but am unsure of the best route.”source ↗
“Not sure how else I can move this sink”source ↗
“Would it be ok to move this to vent straight up directly above the water heater? Or keep the same vent run but move the whole pipe up near the ceiling?”source ↗
“This pipe is such a bad use of space in the back of my garage I really would like it to be out of the way more.”source ↗
“Blower might not be able to handle the extra length:power.”source ↗
Where this came up
People with this problem also raised
- 14Where do I run the vent for a washer installation?
- 7What to do with old water pipes after removing a fixture?
- 2How to route a plumbing vent offset around obstacles
- 22How to fix an off-center toilet drain during a remodel
- 4How to fix a sink drain without removing the P-trap
- 2How do you vent a bathroom that isn't vented?