Slow draining sink and standing water in vent
I live in an apartment and my neighbor and I both have a problem with a slow draining bathroom sink. Our bathrooms share a wall on which the sinks are located. As far as I can tell, the vent pipe runs down vertically through that wall before turning and running horizontally underneath the floor. The showers and toilets drain into the horizontal section and drain fine. I'm guessing the sinks drain into the vertical section. Looking down into the vent from the roof, I can see standing water fairly far down (about where the bend is perhaps).
I'm thinking some debris is lodged at that bend and is responsible for the clogged sinks and visible water. Does this sound likely? Plunging and snaking the sink accomplished nothing. Would the solution be suggesting to my landlord that he needs to rent a beefy auger/snake type device and run it down from the roof? The diameter of the vent is quite large and I imagine a regular snake would just twist about uselessly.
Thanks