Rental income, accommodation sharing, or cost sharing?

[awe123]

My mother lived with me, my spouse, and my 2 children in my primary (and only) residence for 7 months in 2019. She occupied 1 bedroom and shared use in all utilities and services. She paid us rent while she was here. I've read what CRA has to say and I am uncertain as to whether this should be classified as a cost-sharing arrangement or accommodation sharing / rental income.  How do you determine if you are renting below fair market value? What is classified as "a small amount for the upkeep of your house or to cover the cost of groceries"? There seems to be no given monetary threshold. Any input would be appreciated.

[TurboTaxSusan]

"Renting below fair market value (FMV)" would be if you were charging your mother less rent than you would to a stranger living in the same space. If you were renting to a stranger you would be charging them something that you think would make you a profit, or at the very least, what other people renting out similar spaces are charging.

There's also no set amount for "a small amount for the upkeep of your house or to cover the cost of groceries", but generally, if you are "renting" to a family member at less than FMV, the CRA the amounts paid to be a "cost-sharing arrangement or accommodation sharing".