Cadastre and resale: how to read your next home's file

There is a moment, just before signing, when the home stops being a pretty photo and turns into a piece of administrative data. It is when someone types twenty characters into the Sede Electrónica del Catastro and a sober file appears with the address, the square metres, the year, the use, and a small map drawn from above. That file says more about the house than any agency brochure ever will.

If you are buying a resale home in the province of Alicante, your first read should not be the Idealista listing but that file. The query is free, open to anyone, and takes a few minutes at sedecatastro.gob.es.

What the cadastre is and why it matters more for resale

The Catastro Inmobiliario is an administrative registry under the Spanish Ministry of Hacienda that describes every real estate asset in the country. Its founding text is Real Decreto Legislativo 1/2004, the consolidated Cadastre Law, published in the BOE on 8 March 2004.

For new builds, the cadastral file is born fresh: the developer registers the property and the file mirrors the signed project. For resale, the file is the home's geological memory. It has been there since the property was incorporated into the cadastre, sometimes since the 1970s or earlier, and it has accumulated changes layer by layer: an extension, a partial renovation, a change of use, a land segregation. That is why a careful buyer reads it.

Finding your future home with four data points

The fastest way is to know the cadastral reference, that twenty character alphanumeric code unique to each property. If you do not have it, just search by street, number, and municipality. The Sede accepts four routes: cadastral reference, street and number, polygon and parcel for rural land, or coordinates. Descriptive and graphic data are open access. Downloading the cadastral certificate online is also free. In person at the office, that same certification costs 4.48 € for the literal version and 17.8 € for the descriptive and graphic version.

On screen, ordered like a product label, you get the essentials: exact location, built area, year of construction, use (collective dwelling, single family, warehouse), ownership percentage and, almost always, a small aerial view with the property highlighted.

The square metres that look identical and are not

This is where nuance starts. The cadastral file usually expresses the surface as built area including common elements, while the deed typically records the built area without common elements and, sometimes, the useful (interior) area. The useful area is what you walk on: corridors, bedrooms, kitchen, bathrooms, wardrobes. The built area adds walls and partitions. The built area with common elements goes further still and includes a proportional share of the entrance hall, staircases and landings.

That is why a home in the old quarter of Altea can show 92 m² in the cadastre and 84 m² in the deed without anyone having made a mistake: they are different measurements. The figure the bank will use to appraise, and the one a professional valuer reflects in their report, is almost always the built area without commons. There is a practical threshold: if the gap between what your home actually measures and what is registered is below 10 % of the surface, a correction supported by a cadastral certificate is enough. Above 10 %, you need a notarial procedure.

The year, the renovation, and what they tell the mortgage

The construction year shapes half the price. A 1950s flat in Carolinas Bajas, a 1960s building in Benalúa or a late 1980s townhouse in La Zenia are appraised differently because banks look at age the way a doctor looks at lab results: with caution past a certain line. But the cadastre also keeps a renovation year field when there has been a formal declaration. That date, when present, weighs as much as the original year: a full renovation in 2008 technically resets the property in any subsequent appraisal.

If your home is registered as built in 1962 and renovated in 2010 but the seller cannot tell you what works took place, ask for the Property Register's nota simple and the municipal license at Alicante's Ayuntamiento, or whichever town hall applies. A full renovation with structural change requires a license and a cadastral declaration. If neither shows up, it probably was not that comprehensive.

Property not graphically coordinated with the Cadastre

That phrase, hidden in many a nota simple, is one of the most useful findings you will make. It has been around since Ley 13/2015 of 24 June came into force, reforming both the Mortgage Law and the Cadastre Law itself to force cadastral cartography and Register plans to speak the same language. When a property is coordinated, the Register's boundaries match the Cadastre's and you receive a home with an unambiguous geometry. When it is not, look slowly.

In the old quarters of Villajoyosa, Altea, Bocairent or central Alicante (the Raval Roig, San Antón and Santa Cruz neighbourhoods), uncoordinated properties are common: shared dividing walls passed down for centuries, undeclared extensions, inheritance driven segregations. The same happens in many village houses across the inland province, in La Marina Alta and El Comtat. A discrepancy is not necessarily a problem, but anyone who has not spotted it before signing can end up arguing with a neighbour over two metres of patio.

Cadastral value, reference value, and why your ITP is what it is

The cadastral file shows two figures in euros: the cadastral value (valor catastral) and, since 2022, the reference value (valor de referencia). They are not the same thing.

The cadastral value is the basis for IBI and some local taxes. The reference value is the minimum base used by the tax authority to calculate ITP on the resale of housing. The Agència Tributària Valenciana states it bluntly: if the price in the deed is below the reference value, the taxable base is the reference value. In Comunidad Valenciana the general ITP rate in 2026 is 10 % on that base. Translation: if the cadastre sets a reference value of 180,000 € for your flat and you sign at 165,000 €, the tax office calculates ITP on 180,000 €, not on 165,000 €.

Reference values are updated yearly. Those applicable in 2026 were published on 9 October 2025 with their corresponding urban value maps. Before making an offer on a resale home in Alicante, it is worth checking: the data is public at sedecatastro.gob.es and saves you surprises at settlement.

How to fix discrepancies

If after reading the file you spot an error (a surface that does not add up, a use that no longer fits, an extension that was never declared), there are two paths. Small corrections are filed online through the Sede in the subsanación de discrepancias procedure, supported by a cadastral certificate and, if needed, a technical report. Corrections that affect more than 10 % of the registered surface or the outer geometry require a notarial procedure under article 199 or 201 of the Mortgage Law, depending on the case.

In Alicante, the Gerencia Territorial del Catastro is at Calle Reyes Católicos 39, and also handles in person queries by prior appointment. But 80 % of what a buyer needs is solved without setting foot in an office: digital signature, electronic certificate or cl@ve.

Why this step saves trouble

A visit to the Sede Electrónica del Catastro takes fifteen minutes and costs nothing. It will tell you whether the home exists administratively the way it is being sold, whether the property is coordinated with the Register, what surface the administration recognises, what construction year the bank will use to appraise, and what reference value the tax office will look at when calculating your ITP. It is information your agent should give you before the first viewing. If they do not, do it yourself.

For resale, the home does not begin the day you sign: it began decades earlier, in a cadastral file that has been quietly writing every chapter. Reading it well is the first way to take care of what is about to be yours.

If you are looking for a resale home on the Costa Blanca and want to discuss a specific cadastral file, contact us or come explore our properties.