The ten mistakes in one sentence
The costliest mistake when buying a resale flat in Spain is committing money before checking the building and the paperwork. The first payment usually goes with an arras contract, a private deposit agreement signed weeks before the notary, and under article 1454 of the Spanish Civil Code the buyer who walks away loses that deposit. The other nine mistakes have one thing in common: they can all be avoided with documents that already exist and that you can request before signing.
This is not a printable checklist; that is our article on the 15 checks before the arras. Nor is it the general guide on what to check before buying a flat in Spain. It lists the mistakes that cost resale buyers, and foreign buyers in particular, the most money, in the order they tend to happen, with what to do and where to check for each.
[1]Mistake 1: looking at the flat, not the building
A new kitchen tells you nothing about the façade, the roof, the drainage stacks or the structure, and those are paid for by the comunidad de propietarios, the owners' association every flat in a Spanish block belongs to, which means by you according to your share. Buyers spend twenty minutes inside the flat and none in the entrance, the stairwell or the light well, which is exactly where the big bills come from.
What to do: look up the year of construction in the Catastro, walk the common areas and ask for the latest building inspection. In the Valencian Community, for example, the building assessment is compulsory for residential buildings over 50 years old and is valid for 10 years from filing. Where: the property manager (administrador de fincas) and, in some regions, a public register.
[7]Mistake 2: signing the arras with no way out
Many buyers sign the agency's template without reading it carefully, sometimes in a language they do not master. If it is a penitential arras contract and the bank then refuses the mortgage, or a charge turns up in the Land Registry, the deposit can still be lost because the contract did not foresee that case.
What to do: before signing, require in writing what happens if financing is refused, if the nota simple shows charges that are not cancelled or if undeclared levies appear; set a deadline for the deed and state who pays works already approved. Where: the contract itself. Who: an independent lawyer or the notary, before signing rather than after, and a sworn translation if you need one.
[1]Mistake 3: not ordering the nota simple, or trusting the one in the listing
The nota simple is the Land Registry extract for the property. It contains the description of the property, the owner and any charges: mortgages, attachments, usufructs. A copy from months ago shown by the seller may miss a recent entry, and the Spanish Association of Land Registrars points out that the nota simple is for information only.
What to do: order a fresh nota simple yourself a few days before the arras and another before the deed, and check that the seller is the registered owner. Where: the Land Registry or its online office, with the address or the cadastral reference. The nota simple tells you who owns the property; it does not tell you how the building is doing.
[2]Mistake 4: ignoring approved derramas
A derrama is a special levy: an extraordinary payment the owners' meeting shares out among the flats for works or costs that the monthly fee does not cover. If a new façade or lift has been voted but not yet charged, the Horizontal Property Act places levies for improvements on whoever owns the flat when the payment falls due (article 17, rule 11), and that may be you.
What to do: ask for the minutes of recent owners' meetings and for the certificate of debts with the owners' association, which the seller must provide at the deed unless you expressly waive it (article 9.1.e). Where: the property manager. Our article on derramas before buying goes into the detail.
[3]Mistake 5: skipping the energy certificate
The energy rating is not decoration on the listing: it hints at what you will pay for heating and cooling and whether the building will need insulation works. Royal Decree 390/2021 requires the rating to appear in all sale advertising and a copy of the registered certificate to be attached to the sale contract.
What to do: ask for the certificate and look at the letter, the consumption and the date. It is valid for up to ten years, or five if the rating is G (article 13). An expired certificate or a listing without the rating is a question for the seller. Where: the seller and, in some regions, a public register.
[4]What HOUSINGFAX checks from this list
Several of these mistakes can be avoided with public records, and HOUSINGFAX gathers them in one report with 22 checks on official sources: the Catastro record with the year of construction, the registered building inspection in the Valencian Community, the Basque Country and Madrid (with the defects and their deadlines in the Valencian one), the energy certificate where the regional register publishes it, flood zones, a reference price and indicative buying costs. Every figure carries its source and date.
What it does not do: it does not order the nota simple or read the owners' meeting minutes, which remain your job. Start with the free report, which shows the traffic-light rating of each check with your building's real data, then move to the Essential report (€11) or the Complete report (€19), as a PDF within minutes, one-off payment, no account needed, and available in English.
[5][7]Mistake 6: not checking whether it is in a flood zone
A flat on a high floor is not out of reach: the garage, the storage room, the lifts and the entrances still flood, and repairs to common areas are paid for by the owners' association. Many buyers only think about it after a spell of heavy rain, and coastal and river towns popular with foreign buyers are not exempt.
What to do: look up the address in the viewer of the National Flood Zone Mapping System (SNCZI) run by the Ministry for the Ecological Transition, which gives access to the official flood zone maps. Where: the SNCZI viewer or a report that overlays the plot on those layers. If it falls inside a flood zone, ask the property manager about past episodes and check the insurance.
[5]Mistake 7: trusting the asking price
The asking price is the seller's opinion. Without an outside benchmark it is easy to overpay or, conversely, not to ask why a flat is far cheaper than its neighbours. The declared price also affects the purchase tax.
What to do: compare it with public data for the area and check the Catastro reference value. According to the Catastro itself, it is used to set the tax base of the transfer tax on resale homes (Impuesto sobre Transmisiones Patrimoniales) and it cannot exceed market value. If you declare a lower price, the tax is calculated on the reference value. Where: the Catastro online office, with digital identification.
[6]Mistake 8: underestimating buying costs
Many budgets stop at the price and forget what comes next: the transfer tax on resale homes, the notary, the Land Registry, the gestoría (the agency that files the paperwork) and, with a mortgage, the valuation. Foreign buyers add translation, a lawyer and, often, obtaining a tax identification number (NIE). When savings are tight, these costs can force extra borrowing at the last minute.
What to do: work out the costs before you make an offer and keep a margin. Article 1455 of the Civil Code says that, unless agreed otherwise, the seller pays for executing the deed and the buyer for the first copy and later costs. The transfer tax rate depends on the region. Where: your regional government's website, the notary and your bank or gestor.
[1][6]Mistakes 9 and 10: a single viewing and not asking about the building inspection
9. Viewing once, always at the same time. A Saturday at noon will not show a bar's noise at night, the real light in winter, rush-hour traffic or damp that appears after days of rain. Buyers flying in for a weekend are especially exposed. What to do: go back at least once at another time of day, ideally in bad weather, or ask someone you trust to do it; talk to a neighbour in the entrance.
10. Not asking about the building inspection (ITE or IEE in Spanish). It is the document in which a technician lists the defects in the common areas and sets a deadline to repair them; if it is unfavourable, it announces works the owners' association will pay for. What to do: ask the seller or the property manager for the latest one and look at its date, result and pending works. In the Valencian Community and some other regions it is on a public register.
[7]Limits of this list
This list sets out the most frequent mistakes, but it does not replace a lawyer's advice on the contract, the notary on the deed or your bank on financing. Nor does it replace an on-site technical inspection of the building: records show what has been filed, not what lies behind a false ceiling.
If a piece of information is missing, write it down as pending rather than assuming it is fine. A document the seller cannot show is an open question, and an open question before the arras is a good reason to wait or to agree a written condition.
[1][2]Short answers
What is the costliest mistake when buying a resale flat in Spain?
Signing the arras before checking the building and the paperwork. With a penitential arras contract, article 1454 of the Spanish Civil Code lets the buyer withdraw only by losing the deposit, or the seller by paying it back twice over. That is why the nota simple, the owners' minutes, the energy certificate and the building inspection are checked before any money changes hands, not afterwards.
Which documents should I ask the seller for before the arras?
A fresh nota simple from the Land Registry, the energy performance certificate, the latest community fee receipt, recent owners' meeting minutes, the certificate of debts with the owners' association and the latest building inspection if there is one. Together they show who the owner is, which charges exist, which works are approved and roughly what the home will cost to keep.
Does the nota simple show pending derramas?
No. The nota simple describes the property, the owner and the registered charges, and the Spanish Association of Registrars points out that it is for information only. Approved levies appear in the owners' meeting minutes, and debts with the association in the certificate governed by article 9.1.e of the Horizontal Property Act, which the seller requests from the property manager.
How long does it take to check a flat before buying it?
The public-records part, such as the Cadastre, the energy certificate, the flood zone or the reference value, can be ready in minutes with a report that gathers them. What usually takes longest is getting the minutes, the debt certificate and the building inspection from the seller and the property manager, so ask for them as soon as you are seriously interested.
Do these mistakes also apply to a detached house?
Almost all of them. Without an owners' association there are no derramas, minutes or debt certificate, but the nota simple, the arras, the energy certificate and the purchase costs still matter. With a house, the plot, the ground and location risks weigh more, such as the flood zones published by the Spanish Ministry for the Ecological Transition in its national flood mapping system.
Sources you can consult
These references let you review the primary context. Their presence does not turn a source of context into a diagnosis.
- Spanish Civil Code, articles 1454 (arras) and 1455 (deed costs) — BOE (Official State Gazette)Official source verified on 30 September 2026.
- Spanish Association of Land Registrars — What a nota simple or a certificate containsOfficial source verified on 30 September 2026.
- Horizontal Property Act 49/1960, articles 9 and 17 — BOE (Official State Gazette)Official source verified on 30 September 2026.
- Royal Decree 390/2021 on energy performance certification of buildings — BOE (Official State Gazette)Official source verified on 30 September 2026.
- Ministry for the Ecological Transition (MITECO) — National Flood Zone Mapping System (SNCZI)Official source verified on 30 September 2026.
- Dirección General del Catastro (Spanish Cadastre) — FAQ on the reference valueOfficial source verified on 30 September 2026.
- Generalitat Valenciana — Building assessment report for residential buildings (IEEV.CV)Official source verified on 30 September 2026.
Prudent next step
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