We just moved into a new house. The upstairs toilet clogs a couple times per week and the downstairs toilet often takes two flushes. (Our plumber thinks the downstairs problem is just because the toilet is very old, so likely unrelated.)
Other factors:
-Our plumber already ran an auger and confirmed there is no clog in the line
-The offending toilet was replaced (it was a poor model with a small hole so we thought that might be the issue)
-Both before and after replacement, plunging has caused water to drip down the pipe into our downstairs bathroom.
-Before we bought the house, all the pipes were replaced. We think they have thought there was a leak due to the plunging issue– we only figured out it was not a leak because the drywall was not yet put back in the ceiling where it drips out.
-There are no back-ups in any drain, so our plumber does not think it is the vent pipe since that would affect our sinks and tub as well.
I am not very confident in our plumber at this point– we have been dealing with the son in a father/son business and he has to talk to his father for advice since he has no clue what is causing this.
Any suggestions of next steps? Everything I can find on Google does not really apply since we've had no issues at all except for the clogging and leaking while plunging. Everything I can find is either fixed by steps already taken, or has other problems not present.
Best Answer
Since you have already replaced the toilet, we know its not that. Just because the sinks and tub don't have a visible problem, doesn't mean it's not a vent issue. The water flow rate is significantly lower on those, so the potential to pull a vacuum because of POOR air flow through the vent is not there. But the big rush of water from a toilet flush needs a big slug of replacement air from the vent to avoid pulling a vacuum and if there is a bird or rat nest in the vent pipe that restricts that flow, but doesn't totally block it, that will only show up after the toilet flushes.