DD(21), DS(18, PDD-NOS)
5 Furkids (3 Dogs, 2 Cats)
WXH (serial cheater, 12+ OW)
Legally married 18yrs, together 16.5yrs
Note: I edit often for typos/clarity.
Most cats quit using their box when it gets nasty. So these kitties are probably destroying the carpeting. Ick.
In the meantime I would put some renuzit on the floor by her door.
The reason I ask this is because when my sister had cats at her house it used to smell like cat urine at her front door. She cleaned the box daily and it was in the basement. The problem was a neighborhood cat that was left outside would spray my sister's front door. If the apartment doors are outside this could be the issue. Maybe a stray is marking the door because it knows there are cats inside.
Just a thought.