Hi! I have torn up the concrete floor in my basement to make changes to the exising drains and vents. We are moving everything about 90* and adding a sink. Attaching a drawing of what I am thinking. Is is OK to run the vents and drains as shown? My picture is not 3-D, but the vents and drains all go from in ground to vertical. The orange lines go below the pinks lines to access the main. This is close to the design that was there, but adding the sink drain into the w/c drain, will this work? Any help would be fantastic!

Everything looks great... but tell me... does that sink have a vent coming off it and running to other vents?

Hi thanks for the help, the sink does not have a vent, thought it would vent off the toilet vent. I might be able to attach it , where would be best place to hook it? Thanks again

The toilet can be wet vented by the sink... but the sink must have its own vent. Let me explain.

The way you have it now the toilet is vented and you would need to add a vent off the sink and connect back into the vents (run down joist bays to connect to other vents OR run up into attic and connect into vent up there).

OR you could eliminate the individual vent going to the toilet (on right in pic... just cap it) and WET VENT the toilet by rolling a 3x2 wye above centerline of toilet waste line and running to the sink drain (stub out 1.5" to pick up sink) full size 2" all the way until it connects in attic, or down the joist bay to connect into a vent pipe that is at least 2"... no less in size. That make sense?

Anymore questions, just let us know... ok?

And your drawing is perfect! Helps a lot when we can see what we are talking about.. so thank you!

If my answers help, please RATE THIS ANSWER byclicking on rate this answer button and rating. Thank you.

OH! And don't just cap that line at the end of the 4" pipe... bring it to grade someplace outside bathroom and install an END CLEANOUT.. ok? You may need to clear the drain someday and don't want to lift toilet to do so.

While I am on cleanouts.. I would also love to see you install dandy cleanouts on the sink line and the tub vent just as they come out of floor (install 3 feet off floor for tub vent).. see pic. For fitting I am talking about.

These are full size cleanouts and for about 4 dollars now, could save a lot of headaches down the road. Let me know your thoughts! Mark

Hi great answers. I just want to make sure I got the right idea. Right now only the main line and the vents are there. So if I leave the 2"vent off the toilet line can I just reroute that vent to the top side behind the toilet and hook it to the sink line ? it should be above centerline of 3" line? The main line where the cap is will be below tub, witch is against wall, so not sure how I could add a cleanout. Thanks again you are awsome to help us like this

No on the reroute of vent from toilet back around to connect into sink drain... that would just be a closed loop... bad for everything. I also wanted to see if you can install the tub waste into the three inch as well... not past the toilet drain like you have it.

The cleanout... hmmm... any chance can run it out of the room to an unfinished area.. or not? Get back to me.

I have attached another drawing. I'm not quite sure that I understand about attaching the sink vent as a wet vent. I moved a few things on the drawing to what I think you may be getting at. Hopefully I can do all of this in the floor, since the two side walls are block. Hope this makes sense, let me know what you think of plan B.

Looks great at this point... but, you are not going to like this part:

Picture looks good.. except that sink vent again... I know you are trying to use the old vent... and maybe I have not been clear (I am sure this is it by the way)...

BUT the vent for the sink must connect above the sink.. that is the vent for the sink must come off the top of the tee fitting that stubs out to pick up the sink drain... and that vent must then connect into vent system so it ties in at least 6 inches above the sink top and then ties into other vents in this bathroom or goes into upstairs space or attic and connects full size into vent system (2").

Let me show you a picture... you have the underground part of this fine (except eliminate that toilet vent headed to right)... above ground needs to look like the picture... minus the septic tank.

Hope that helps... let me know.

If this helped, please RATE THIS ANSWER. Thank you... MARK

Now I get it!! Sorry I have a hard time visulizing without a picture.you have been a great help thanks so much. Moe I tried to rate your answer, but you helped me before and it will not let me rate you again. But I will when it will let me. You saved me a lot of problems down the road.