He showed up this morning and was gone after 45 minutes and $89. Seriously.
The funny thing is that he had no idea why the washer water decided to make an appearance upstairs either. There wasn’t any water coming up through the floor drain in the basement, which meant that it wasn’t the sewer (which is good). He figured that since the kitchen and bathroom sinks were clearly clogged, a good place to start would be to snake out the kitchen drain. The kitchen and bathroom sinks share a common drain, so it was really like killing two birds with one stone. He found a ginormous hair clog waaaaaaaaaaay down in the pipe, he’s guessing it was below the basement floor. And now (apparently) my plumbing system is doing just fine (I was brave enough to wash another load of laundry tonight, and it was extremely uneventful). Although I did have some serious cleaning to do (I don’t know if I’ll ever be able to look at my kitchen sink the same way).