How to check an Idealista listing before buying

You have found a flat on a property portal such as Idealista or Fotocasa. The photos look good and the price is within budget. But a listing only shows what the seller wants you to see. Before arranging a viewing, making an offer, or signing anything, you should check what the listing leaves out: risks, legal status, and the property's true floor area.

This guide gives you a checklist for verifying any listing in minutes using official data, so you do not face costly surprises after buying.

What an Idealista or Fotocasa listing does not tell you

Property portals are shop windows: they show photos, floor area, and price, but not the property's less attractive side. Yet that is precisely what could change your decision—or the price.

• Environmental risks: whether the plot is at risk of river or coastal flooding, or lies in a radon or seismic-risk area.
• Potential nuisances nearby: roads, railway lines, airports, high-voltage power lines, or industrial land.
• Planning status: the land classification and any restrictions affecting refurbishment or extensions.
• True floor area: the area stated in the listing does not always match the Cadastre.
• Fair price: whether the asking price reflects the area's true market value or is inflated.

Checklist: how to verify a listing before viewing or making an offer

• Pinpoint the exact property on the map and obtain its cadastral reference.
• Check the specific plot's river and coastal flood risk.
• Review the municipality's radon and seismic risk.
• Examine the surroundings: road traffic, railways, airports, industry, and power lines.
• Compare the listing's floor area with the Cadastre and check the property's occupancy status.
• Check the building's age and whether a technical inspection (ITE/IEE) is due.
• Compare the price with the area's true market value before making an offer.

Step 1: pinpoint the exact property

Many listings provide only the general area rather than the full address. Ask the seller or agent for the cadastral reference or exact address before making a decision. If you are unsure which identifier you need, read our guide to what a cadastral reference is.

Step 2: check risks and official data in minutes

Carrying out these checks manually means jumping between the Cadastre, the SNCZI flood-map viewer, radon and seismic maps, and local planning documents. Hogarfax does it for you: enter the address or cadastral reference to obtain a complete profile of the property—flooding, radon, seismicity, planning, surroundings, floor area, condition, and price—using official data in a single report.

If you are still assessing the general area, start with the property risks by municipality; once you have a specific listing, analyse the exact property.