How to install plumbing for toilet and shower in basement need to know

Let's do it right and add a vanity to your basement bath. Toilet connects to sewer main. Vanity connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The toilet wet vents through the vanity vent and the tub/shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book in 90 percent of the country. Check your local codes to make sure you're not in the excluded 10 percent.. The vent off the lavatory may be run out the roof or revented back into a dry vent in the attic or if you're reventing back into a fixtures dry vent you must make your connection at least 6 inches over that fixtures flood rim. Good luck and thank you for rating my answer. Tom

Toilet to main drain.
Shower to main drain.
Vanity to main drain .
Shower vented back to vanity pipe

Try this!
Toilet to main drain.
Vanity to main drain and a vent run from the tee out the roof or tied back to a existing roof vent in the attic.
Shower to vanity drain where it will be wet vented by it. Regards, Tom