@bofaur , Do you still need help on this?
From your post
(a) I am assuming that the city / locality distinguishes properties as "residence" ( with a lower tax rate or a discount of some kind ) and Non-Residence/ Income ( for a standard prop tax treatment ). The designation therefore is only valid for the city/locality tax purposes.
(b) For Federal ( and State ) tax purposes, it is the usage of the property that determines how you report the property expenses ( and incomes if any ). Thus if you actually use the property ( as you mentioned in your post ) as a second / vacation home but temporarily used by a relative and there is NIL expenses paid by the relative for the use of the property ( directly or indirectly), then you could argue that this is a second home and not income property. This is a tricky area and you have to be careful that there is no benefit ( monetary or otherwise)to you in exchange for the relative's use of the property.
Is there more I can do for you ?
