I have an older 1 3/4 storey home. The upstairs has been renovated and a two piece bathroom installed. I'd like to know if the drainage has been installed correctly. There is a 3" stack in the house which services the main floor bathroom and the second storey bathroom. On the second floor a 3" pipe comes off the stack and runs horizontally about 10 ft to the toilet where it wyes to the fixture itself. After the wye, the pipe is reduced to 1 1/2 inch and moves up diagonally towards the lavatory drain where it t-wyes to the lav drain itself. After the lav drain it continues upwards as a vent and then elbows back to the main stack itself. Does this sound acceptable? I have read that the lav drain should tie in downstream of the toilet and then vent either back to the stack or up through the roof. It would be quite easy to put this vent through the roof. Also, does the vent need to be bigger than 1 1/2 inches.

Thanks

Hi Pants:


If that lavatory drain/vent is the wet vent for the toilet then it should be 2" in size.

Further, the vent for the toilet should roll above the center line of the toilet pipe although some inspectors will allow you to run the pipe off the end like you say has happened here.

If everything works well at this point I wouldn't go changing things, but I have to guess you are having issues OR this is a new install perhaps..

Why are you asking?

Mark

Thanks Mark,

Yes this works fine, (in fact they are the best working drains in the house). However, I am considering selling the house and want to know if this will pass inspection or be flagged.

No way it will get flagged. Most home inspectors are looking for real issues... not whether plumbing design is bad as much as whether there are leaks or real health hazards! You should be fine.

Good luck with the sale...

Mark

Thanks again.