from pub 527, "If you hold property for rental purposes, you may be able to deduct your ordinary and necessary expenses (including depreciation) for managing, conserving, or maintaining the property while the property is vacant. However, you can’t deduct any loss of rental income for the period the property is vacant.". Here is link to pub 527:

https://www.irs.gov/publications/p527#en_US_2017_publink1000219000