The not-for-profit rental income is reported as follows and can be found in IRS Publication 527 (page 25).
Where to report.
Report your not-for-profit rental income on Schedule 1 (Form 1040), line 8. If you itemize your deductions, include your mortgage interest and mortgage insurance premiums (if you use the property as your main home or second home), real estate taxes, and casualty losses from your not-for-profit rental activity when figuring the amount you can deduct on Schedule A.
Sign into your TurboTax account:
Click Federal in the left column
Click Wages & Income at the top
Scroll down to Less Common Income. Click Show more
Start Miscellaneous Income, 1099-A, 1099-C
Start Other reportable income
Say Yes to Any Other Taxable Income?
Enter a description and amount
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When you rent to a family member below fair market value, as far as the IRS is concerned you don't have a rental property; you have personal use of a home. If you itemize deductions, you can deduct the property taxes and mortgage interest - assuming it otherwise qualifies as deductible. You can't deduct any other expenses associated with the property. You report the income as described above by @DianeW777.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.