If you want to consider the amount received as rent, then it would be a not-for-profit rental which is covered in IRS Publication 523 on page 16 - <a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/p527.pdf#page=16">https://www.irs.gov/pub/irs-pdf/p527.pdf#page=16</...>
"If you do not rent your property to make a profit, you can deduct your rental expenses only up to the amount of your rental income. You cannot deduct a loss or carry forward to the next year any rental expenses that are more than your rental income for the year."
Otherwise any amounts received from your room-mate is shared expenses and not reported on your federal tax return.
You can still deduct the mortgage interest and property taxes as itemized deductions on Schedule A of the tax return as the owner of the property.
