Tub waste into a plumbing vent

We are looking to install a washer & dryer on our second floor. The room that we want to install them in is immediately over a full bath (tub/shower, toilet, sink). Can we "45" into the vent pipe that likely servicing the 1st floor bath, with the washer waste water hose?

Or, will we need to run the washer drain line to the basement and tie-into the 1st floor bathroom waste line below the 1st floor bathroom?

Thanks

Don't do it, Not a good idea.

Don't do it, Not a good idea.

The washer will need to drop down a floor and connect below.

A vent should remain dry, or it's "not" a vent.

There are case where something really light duty like a lav rated at one fixture unit is allowed a very short wet vent section if the pipe in one size larger.

That is not your case here.
Putting that much water down the vent could cause overflowing of the fixtures below.

Unfortunately, I thought that would be the answer.

Since we need to run H & C lines to the second floor, I'm not certain why I feel so tired when I think about running an 1-1/2 PVC to the basement.

Oh well, guess we'll find out how badly we want the 2nd floor laundry.

drain

If running a 1 1/2" line to the basement, and I hope you are considering installing a trap and vent with it, imagine how you are going to feel when you find out it should have been a 2" line.