They have regular basement stairs going down, and there is even a dumbwaiter going up from the basement so I assume they were going to put the kitchen in the basement.

The apt does not have its own entrance from the exterior; it must be accessed from the interior of the home via a basement door and stairs off of the living / kitchen area.* The main home is 2900 sq ft (3 bed/ 2.5 bath) and has 2-floors.

Some nurses lived up stairs, which was fine.

But a situation happened just recently to cement this.I'm dealing with a headache of an inherited tenant who I'm probably going to evict.

I was caught off guard so I just told him we were here to meet someone and walked past him up the stairs.

This hallway has stairs that go up to the second apartment. 

My rental has a basement, but it's low ceiling, has narrow and a bit steep stairs and is hazardous in general.  

There is also sticky spilled mixed drinks on the wood floors, walls, and wood stairs.

I rehabbed one many years ago and left the original asbestos siding in place but did replace the cracked and broken tiles with the newer cement fiber shingles. 

Hanging on them are beach towels, bikinis, shorts etc...that's what kind of triggered the thought of what if my tenants were to do this in my multi-unit buildings, whether it's hanging in a corner in a common area, or draped on railings of stairs or balconies...I do not have anything in my lease or rule book addressing this.