You should report your rental income and expenses from your self-storage units on Schedule E.
To navigate to this input in TurboTax Premier:
- Click the Federal Taxes tab
- Click Wages & Income
- Scroll down to the Rental Properties and Royalties section
- Click the blue Show More for this section
- Click Start (or Revisit) next to Rental Properties and Royalties (Sch E)
Please see attachment for reference.