What do I have to prove to claim for a defective product?

Question

José Manuel Alburquerque · Accepted Answer

You have to prove that the product was defective, that you suffered damage and that the damage was caused by that defect. You do not have to prove that the manufacturer acted wrongly or that it was at fault. A product is defective if it does not provide the safety that could be expected of it, taking into account how it was presented, the use to which it could reasonably be put and the time when it was released onto the market. It is not always necessary to explain the fault in technical terms, because the judge may treat the defect as proved on the basis of serious and consistent indications, such as the device having caught fire during normal use with no other possible cause. What counts as a defect A product that simply does not work properly is not defective for these purposes. That is claimed under the guarantee. What is defective is a product that turns out to be unsafe, for example for one of these reasons: A manufacturing fault, which means that the unit in question is not as safe as the others in the same series. A dangerous design. Insufficient instructions or warnings, because the law takes into account how the product is presented. The manufacturer is also liable for misuse that it could have foreseen. If you used the product in a way that clearly went against the instructions, the compensation may be reduced or eliminated. And a product is not defective merely because a better version is later released onto the market. How to prove it Keep the product and what is left of it exactly as it was, without repairing or cleaning it. If the manufacturer or its insurer wants to examine it, make sure it is done with you or your expert present and that a written record is made of the condition in which it is handed over. Take photos and videos and keep the receipt or the invoice, the packaging and the manual. Ask for any reports that exist, such as the fire brigade's report, the emergency department's report or the police report. Commission a report from an expert on the origin of the damage. It is usually the most important piece of evidence. Check whether the product has been withdrawn from the market or has any alert on Safety Gate, the EU alert system for dangerous products, or with the “Agència Catalana del Consum”, the Catalan consumer agency. What the manufacturer can argue It escapes liability if it proves, for example, that the defect did not exist when it placed the product on the market, that the defect is due to compliance with a mandatory rule or that the scientific and technical knowledge at that time did not make it possible to detect it. Manufacturers of medicines and food cannot use this last defence. For products placed on the market after 9 December 2026, an EU directive will make proof easier. The judge will be able to order the manufacturer to produce the evidence in its possession. The defect will be presumed if the manufacturer does not produce it, if the product breaches mandatory safety rules or if the damage is due to an obvious malfunction during normal use. Spain has to incorporate the directive into its law and, as of October 2026, there is no record that it has done so.