It is unlikely that you could legally classify it as a rental, unless your mother were paying fair market value on the rent. The IRS considers it a personal use dwelling under the following conditions (IRS Tax Topic 414):
A day of personal use of a dwelling unit is any day that it is
used by:
- You or any other person who has an interest in it, unless you
rent your interest to another owner as his or her main home under
a shared equity financing agreement
-
A member of your family or of a family of any other person who
has an interest in it, unless the family member uses it as his or
her main home and pays a fair rental price
- Anyone under an agreement that lets you use some other dwelling
unit
- Anyone at less than fair rental price
When you treat it properly as a second home, you can deduct mortgage interest and property taxes on Schedule A, just like you can for your primary residence.
