In absence of cadastral value, you must use the provisions established for the ‘Impuesto de Patrimonio’ or wealth tax in order to calculate the value of your property.
Section 10 of our wealth tax Act provides that you have to choose the higher value among:
1º Cadastral Value. You don’t have
2º Official value used to calculate another tax such as Transfer Tax ITP or Inheritance tax
3º Escritura value