Steone: The question is if a non resident who does not own any property in his own country but owns a property in Spain does he have to pay ´wealth tax´?
I think may be you are confusing Patrimonial Tax (wealth tax) with imputed tax, the so called ‘second home tax’.
As stated the patrimonio tax does not affect the average owner, but if you own a property or properties in Spain when you are not resident in Spain then you must pay the tax on each property you own.
For interest: My son is non-resident, he has 2 apartments and a separate parking space in a garage. He pays tax on all three properties.
For interest.
Residents in Spain pay the tax, in their annual tax return, on all properties, other than their main home, where ever they are in Spain or the world. Thus if as a Resident, one owns say one property, their main home, and a store room and parking space, unless they are included in the same Escritura, they pay tax on the store room and the parking space.
In addition to my home, I have a lock up garage nearby, I pay the tax on that. My wife, resident in Spain, owns a house in Philippines she pays imputed tax on that house ( to Hacienda) here in Spain.
More 'light reading' here:- http://www.lawbird.com/services/fiscal_representation_faq