Is radon a serious risk in Spanish properties?

Yes, in specific regions. Spain's Consejo de Seguridad Nuclear classifies parts of Galicia, Extremadura, Castilla y León and inland Andalucía as high-priority radon zones (Zone 3), with average indoor concentrations above 300 Bq/m³. The WHO recommends action above 100 Bq/m³. Radon is responsible for the second highest number of lung cancer deaths in Europe after smoking, and most Spanish homes in risk zones have never been measured.

How do I know if a Spanish property is in a radon risk zone?

The Consejo de Seguridad Nuclear (CSN) publishes the radon priority zone classification for all Spanish municipalities on their website. A Hogarfax property report also includes the official CSN radon zone classification for the property's location. However, zone classification is only indicative — the only way to know the actual radon level in a specific property is a physical measurement.

Do Spanish sellers have to disclose radon levels?

Currently, there is no legal obligation in Spain to measure or disclose radon levels in property transactions, unlike in some US states. However, a seller who knows of elevated radon and conceals it could face liability for undisclosed defects (vicios ocultos) under Spanish civil law. It is always the buyer's responsibility to request a measurement if buying in a risk area.

Can radon be fixed in an existing property?

Yes. Active sub-slab depressurisation (extracción activa bajo la solera) is highly effective and can reduce indoor radon by 50-90%. Installation costs typically range from €1,500 to €5,000 depending on the property's construction type. If you discover elevated radon during due diligence, it can be used as a price negotiation point or made a condition of the sale.