Adding bathroom vanity to second bathroom on first sloor. Already added toilet. Need to tie in to existing pvc sewer line

You need to connect the drain and the vent for the sink, right?

If you can find the toilet vent and WET VENTING is allowed in your area then you may be able to connect the sink drain into the toilet vent and let the toilet vent act as the vent for the sink... ;)

I would need more info. To tell you more on this, OK? What pipe size, how are you going to vent the sink? How far is the sink from the drain line, etc...

Back to you...

Mark