As Roberto says you will have a tax liability for the property which in not your main home.
Tax residents in Spain are obliged to pay tax on all properties, worldwide, which are in addition to their main home in Spain.
My wife has a property in Philippines which is used rent free by her family. We are obliged to declare that in our annual income tax returns and pay the imputed tax..
I also have a lock up garage in Spain. That too must be declared, resulting in additional tax.
A garage space, even a trastero (storeroom) etc. which is not included in the Escritura for one's main home, incurs imputed tax.
Until you move to Spain you will of course have the imputed tax to pay on any and all properties you own in Spain. I believe if they are rented out then you pay income tax on the income derived and imputed tax only for any period when the property is not creating an income.
Alan, you said you will be moving to Spain.
Immediately from the time you move to Spain you will become tax resident. The 3 mths / 183 days rules do not apply to those who move here.
This message was last edited by johnzx on 03/11/2016.