Yes, you can deduct storage costs as a rental expense under "Other Expenses". When going through the expense section, you will be able to enter your own description (such as utilities for storage rent) and the amount. The data entry appears after common expenses, mortgage interest are entered. Continue through the interview until you arrive at Any Other Expenses screen. Please see attached picture.
https://dqjghx1vau0u.cloudfront.net/uploads/assets/54679/original.png?1460402086
