You established a "California-source" business activity (purchased and listed the property in 2025 as a rental).
Even though the tenant didn't move in until 2026, the IRS and the California Franchise Tax Board (FTB) consider a property "placed in service" the moment it is available and listed for rent (December 14, 2025).
Thus, you can begin claiming pro-rated expenses for 2025 (depreciation for the last 17 days of the year, property management fees, advertising, etc.).
You generally must file a Form 540NR if:
- You have any California-source income (even $1 of gross rent) .OR
- your worldwide gross income exceeds CA’s filing threshold (for 2025... $22,941 for a single filer under 65).
Filing a 2025 return allows you to "document" any start-up costs. California allows you to carry-over passive rental losses to future years to offset future rental profits.
- Open or continue your return.
- In the "Personal Info" section, set your Resident State to your actual home state.
- Select California (when the program asks if you "earned money in another state", This will generate Schedule CA (540NR), which separates your total income from your CA-source income.