Note that it "DOES" "NOT" matter what the start/end date period the property taxes are for. It only matters in what tax year you actually pay those property taxes.
- Say you pay property taxes for a one year period that starts on 4/1/2021 and ends on 4/1/2022.
- You converted the property from personal use to a rental on 6/1/2021.
If you paid those property taxes on or before 12/31/2021 then those taxes are prorated based on a tax year from 1 Jan - 31 Dec. With an in service date of 6/1/2021 that would mean 5 months of personal use (5/12 of the amount on SCH A) and 7 months of business use. (7/12 of the amount on SCH E)
Same holds for the property insurance, with 7/12 of the amount on SCH E, and nothing on SCH A since insurance is not deductible as a SCH A itemized deduction.
Whereas if you paid the property tax on 1/1/2022 and the property remained as a rental for the entire 2022 tax year, then on your 2022 tax return you would claim property taxes for the entire 2022 tax year.
