I'm planning on paying the property taxes of a home my mother-in-law owns. She owns the house, but I live there. As part of the bargain, I agreed to pay the property taxes.
If I write the check directly to the State/County, can I write it off on my year end taxes?
According to page 107 of the instructions for schedule A for form 1040 :
Include taxes (state, local, or foreign) paid on real estate you own that was not used for business. ...
If you want to make a business out of her property and be her agent in the management, you might be able to work with an accountant on this, but it won't be a valid personal deduction.
To make matters worse, if you pay the property tax your mother in law can't take the deduction either. You may be better off paying rent and having her handle the property correctly, as a rental.
You cannot deduct. Even if you could, unless you also hold the mortgage, it's unlikely that you would have sufficient deductions to exceed the standard deduction for a married couple.
