I recently bought a duplex. Much of the plumbing had been updated poorly or still had the existing cast iron/galvanized steel pipes. I had a plumber come and replace the old cast iron/steel drainage pipes with PVC.
The attached photo is a second floor back to back sink with the neighboring unit. Both units share the same venting and drain. The drain is used only for the two bathroom sinks and runs straight down into the basement where it connects to the horizontal waste.
The initial plumber finished his work but left our sink drain rough in un-capped. Once, while this drain was un-capped, the neighbor used their bathroom and water poured out from the open drain on our side. We asked the plumber about this and the solution was to cap the rough in. I'm concerned that something about this set up is incorrect. Since then I've had multiple plumbers come and look. I get a different explanation/solution every time. After looking through codes and your forum I still have questions about the proper way to plumb and vent this location. I would greatly appreciate some expert feedback about this area before spending more money on rework or closing this wall.
1. What would cause water to back up into a sink drain that is located above the drain being used?
2. Does the PVC to Galvanized vent location need to be updated to a shielded coupling?
3. Are the drain lines properly plumbed as shown?
4. Is the vent routing properly plumbed as shown?
The attached photo is a second floor back to back sink with the neighboring unit. Both units share the same venting and drain. The drain is used only for the two bathroom sinks and runs straight down into the basement where it connects to the horizontal waste.
The initial plumber finished his work but left our sink drain rough in un-capped. Once, while this drain was un-capped, the neighbor used their bathroom and water poured out from the open drain on our side. We asked the plumber about this and the solution was to cap the rough in. I'm concerned that something about this set up is incorrect. Since then I've had multiple plumbers come and look. I get a different explanation/solution every time. After looking through codes and your forum I still have questions about the proper way to plumb and vent this location. I would greatly appreciate some expert feedback about this area before spending more money on rework or closing this wall.
1. What would cause water to back up into a sink drain that is located above the drain being used?
2. Does the PVC to Galvanized vent location need to be updated to a shielded coupling?
3. Are the drain lines properly plumbed as shown?
4. Is the vent routing properly plumbed as shown?