orangetrader wrote:
I cannot do a laundry sink. A laundry sink will result in a lower elevation
than the kitchen sink, so there is no way I will be able to run a length of
pipe about 6' long and still be able to tie into the kitchen drain at a
higher elevation.


SNIP

Actually, you want to tie into the drain *after* the sink trap.
That would mean *lower* than the trap outlet.
And it would all be inside the wall.

The washer dumps a *huge* amount of water all at once.
The drain has to be big enough to handle that without backup.
As I said before, if the drain (in the wall) for the sink is 2"
it *should* work to add the washer. But there are venting issues
and (locally) the connection may not be permitted.

You're in uncharted waters here and I think you need some
competent advice from someone local who can look at it.

Jim