Sorry I took so long to answer; it's been somewhat hectic for the past week.
Judy, I cannot provide the exact section of the IRC, but if you review Chapter 9 of IRS Pub 17 or download IRS Pub 527, it becomes obvious from the examples that the rental of a room in your mother's home will always fall in the category of "Dwelling Unit Used as Home". That being the case, the expenses associated with the room rental (pro-rated share of utilities/taxes/mortgage/repairs, etc.) are limited to the amount equal to the rent collected.
BOTTOM LINE: You CANNOT show a loss (paper or otherwise) associated with the rental of a room in your home.
Since that is the case, I have always held the position that claiming such rent on a Schedule E that shows NO taxable income or NO tax-deductible LOSS is a waste of everyone's time and effort and needlessly complicates the tax return. Conversations I have had with numerous IRS officials has confirmed this position, provided I could show (if asked) that the expenses clearly exceeded the rent received.
Now, as I understand it, your mother DID rent the room to the student, but failed to report the income. I suspect that the student somehow claimed the rent as a deduction (international graduate students do this routinely, as do students on internships) and that is how the IRS determined she had taxable rental income. They then sent her an adjustment notice, adding the income to her Adjusted Gross Income without factoring in allowable rental costs. I suspect she probably just accepted the IRS ruling and failed to amend her return to show that her expenses exceeded her income.
If this happened with the last few years (2007 or later), we can fix it with an amendment and get her money back, plus the penalties and interest. Email me at
[email protected] if you wish to pursue it.