No double benefit allowed. If any portion of property taxes paid on your principal residence was deducted as an expense on federal Schedule C, C-EZ, E or F, then that amount cannot also be deducted. See the following example.
Example: Jean used one room of her home for her business. She deducted $200 Indiana property tax as an expense on her federal Schedule C. She paid a total of $1,200 Indiana property tax on her home. Jean's deduction will be $1,000 ($1,200 minus the $200 deduction on federal Schedule C).