I have a dual sink with two drains connected to separate wall entries. One works fine but the one with the disposal only drains if the disposal is run. Even after it is runs, some water sits in the unit. A local plumber says the internal wall plumbing needs to be rebuilt as it is permanently blocked with hardened materials and he can’t get his large router through it.
I would try a plunger when it has some water in the pipes. If that dont work try renting or purchasing a snake of your own, I;ve had good luck w/ mine. Sometimes you can’t trust plumbers. You can always snake it – but sometimes it’s harder than others. If that dont work try another plumber. Good luck Kev
The sink drains when the disposer is run because it is pumping the water up and across to the other sink through the vent system. It would be an unusual sink drain that was rusted so badly that an auger could not be used to clean it. You need a better plumber.