Basement plumbing rough-in

[shifrbv]

I decided to install basement bathroom.

Installed new basin, run 3" PVC pipe for toilet, tub, sink drains ensured 1/4" slope per foot, filled with water no leaks everything is a OK. Ready to concrete

Oh wait, there is a leak, where 3" pipe enters basin...

So question would be how should I sealed pipe that enter sewage pit?

( I know if pump is working water level should never get that high, and yet I feel need to seal...)

Thanks, Brian

[RBM]

Is the fitting that comes with the basin, for 3" or 4" ?

[shifrbv]

Just 3" hole on the side of the basin....

[RBM]

Is it just a hole, or is it a fitting or rubber bushing?