What does principle residences means for the California renters credit?

[MaryK1]

Yes if you pay rent to your brother for a room and you meet the other qualifications, you can claim the credit.

You must meet all of the following to qualify:

1. You were a California resident for the entire year.
2. Your California adjusted gross income (AGI) is:

• $40,078 or less if your filing status is single or married/RDP filing separately.
• $80,156 or less if you are married/RDP filing jointly, head of household, or qualified widow(er).

You paid rent for at least half the year for property in California that was your principal residence.

The property you rented was not exempt from California property tax.

You did not live with another person for more than half the year (such as a parent) who claimed you as a dependent.

You were not a minor living with and under the care of a parent, foster parent, or legal guardian.

You or your spouse/RDP was not granted a homeowner's property tax exemption during the tax year.

Nonrefundable Renter Credit | California Franchise Tax Board

[Critter]

Of course if you take this credit your brother will need to report the rental income on his return.