Spain charges you tax if you rent the property out. If you don't rent the property out, it imputes a rent and you are charged tax on the imputed rent.

The cadastral value is (finger in the air) 40% of the value of the property; you pay (non-eu resident) 24% of between 1.1% and 2% of the cadastral value.

So 0.1%-0.2% of property value annually.