Renting a storage unit is a common expense, but whether you can deduct it depends entirely on what you are storing and why. If you store business inventory, equipment, or documents in the unit, the rental cost is deductible as a business expense. A rental property owner who stores tools and supplies used for the property can deduct the storage costs as a rental expense. Personal storage for household overflow, furniture, or belongings you simply do not have room for at home is not deductible. Keep clear records showing that the storage unit is used for business or income-producing purposes to support the deduction.