The Due Diligence Clause That Decides Whether You Get Your Deposit Back

International buyers who instruct a lawyer for a property purchase in Spain understand, correctly, that legal due diligence is what protects them. What fewer buyers understand is that due diligence is only as effective as the contract clause that governs it. A thorough investigation carried out under a poorly drafted clause can still leave you negotiating for your deposit back, rather than exercising a clear contractual right to walk away.

This distinction matters more than it appears at first reading, and it is one I see misunderstood repeatedly, even by buyers who have taken sound advice on the investigation itself.

"Subject to due diligence" is not a clause. It is a placeholder.

Most reservation agreements in the Spanish property market include a line stating that the purchase is "subject to due diligence" or "subject to satisfactory legal checks." On its own, that phrase carries very little legal weight. It does not tell you what counts as a problem, how long you have to find one, or what happens once you do. Without those three elements defined, the clause is an intention, not an enforceable right.

What a properly drafted due diligence clause must answer

A clause that actually protects a buyer needs to resolve three questions before the deposit is paid, not after.

First: what counts as a problem? The clause should specify the categories of issue that trigger the buyer's rights: outstanding charges or debts on the property, planning or urban law irregularities, missing or non-compliant licences, illegal extensions, or defects in the chain of title. A vague reference to "legal issues" leaves room for a seller, or their lawyer, to argue that a genuine problem falls outside what was agreed.

Second: how much time does the buyer have? The investigation and notification period needs a fixed deadline, stated in days, running from a clear starting point (signature of the agreement, or receipt of documentation, for example). Open-ended language creates disputes about whether the buyer acted in time, exactly when it matters most.

Third: what is the consequence? This is the element most often left unresolved, and the most consequential. If the contract does not state clearly what happens when the buyer exercises the clause, the buyer is left negotiating the outcome from a position of uncertainty, precisely when they believed they held a contractual right to exit and recover their deposit.

A case that illustrates the gap

I have advised on a transaction in southern Spain where the due diligence process worked exactly as it should: it uncovered a real, documented issue with the property before completion. What failed was not the investigation, but the drafting of the reservation agreement signed before it began. Because the consequence clause was not precise enough, the buyer did not have a clean, contractual exit. Instead of simply exercising a defined right, we negotiated the return of the deposit from a position that should never have required negotiation.

That outcome, a favourable one in the end, cost time, leverage, and certainty that a properly drafted clause would have preserved from the outset.

Why this matters before you sign, not after

A reservation agreement exists to take the property off the market. For a buyer investing significant capital in a jurisdiction they do not fully know, it should do more than that: it should protect the buyer during the period in which they are still confirming what they are actually acquiring.

Before paying a reservation deposit on a property in Spain, the question to ask is not "does this contract have a due diligence clause?" Most do, in some form. The question is: "what, precisely, does this clause say happens if due diligence finds a problem?" If the answer is not written down, in plain terms, before you sign, you are relying on goodwill at the exact moment goodwill is least reliable.

Buyers considering a property purchase on the Costa del Sol are welcome to have their reservation agreement reviewed before signing. A short review at this stage is considerably cheaper than a negotiation after the fact.