Slab-on-grade houses sink here in Houston, and we had a company raise ours and redo the underground plumbing. About a week after the work was done we noticed that flushing one Toto back-to-back toilet pulled water from the other. It doesn't matter which toilet is flushed, it happens both ways.
Terry's YouTube video on back-to-back toilets was awesome and immediately identified the mistake our plumbers had made:
We showed the company the video and they researched it, pulled all the dirt back out, and redid the plumbing. To my eyes (that know nothing about plumbing) it looks like they did it the way Terry showed in the video:
This change did not affect the toilets. Flushing one still pulled water from the other.
Next, they suspected the venting. The new 3" vent they installed below ground connected to an existing 2 inch vent behind the wall. They opened the wall and cut the pipe so that the 3" vent was wide open about 18" above the toilet. Their goal was to give this maximum venting and see if it helped. They did not think the 2" vent was the problem, but it was worth a try even though we opened the wall to do it.
This did not reduce the amount of water being pulled, so they reconnected the vent as shown in the photo.
At this point they are stumped. I hope someone can suggest a next step.
Thanks for any help in advance!
Signed: Desperate to flush in Houston (still have a little sense of humor left....)
Terry's YouTube video on back-to-back toilets was awesome and immediately identified the mistake our plumbers had made:
We showed the company the video and they researched it, pulled all the dirt back out, and redid the plumbing. To my eyes (that know nothing about plumbing) it looks like they did it the way Terry showed in the video:
This change did not affect the toilets. Flushing one still pulled water from the other.
Next, they suspected the venting. The new 3" vent they installed below ground connected to an existing 2 inch vent behind the wall. They opened the wall and cut the pipe so that the 3" vent was wide open about 18" above the toilet. Their goal was to give this maximum venting and see if it helped. They did not think the 2" vent was the problem, but it was worth a try even though we opened the wall to do it.
This did not reduce the amount of water being pulled, so they reconnected the vent as shown in the photo.
At this point they are stumped. I hope someone can suggest a next step.
Thanks for any help in advance!
Signed: Desperate to flush in Houston (still have a little sense of humor left....)