Regulation (EC) No 648/2004 on detergents has, since 2005, laid down biodegradability requirements applicable to surfactants used in detergents. These requirements condition their placing on the market and distinguish between two levels of biodegradation: primary and ultimate.
The current Regulation has been replaced by Regulation (EU) 2026/405, which was published in the Official Journal and entered into force last March. However, it will not come into effect until September 2029, with Regulation 648/2004 remaining fully in force until that date. With regard to biodegradability alone, this new text significantly modifies the approach adopted to date: it broadens the scope to include new components, refocuses the requirements applicable to surfactants on ultimate aerobic biodegradation, and removes the derogation mechanism based, in particular, on primary biodegradation. These changes, which will be phased in between 2029 and 2034, nevertheless require manufacturers in the sector to start preparing for them now.
Implementation roadmap
- 22 March 2026: entry into force of Regulation (EU) 2026/405 (start of the 42-month transition period).
- 23 September 2029: application of the new Regulation and repeal of Regulation 648/2004.
- 23 March 2032: biodegradability requirements – mandatory compliance for water-soluble polymer films.
- 23 March 2034: biodegradability requirements – mandatory compliance for organic substances intentionally added at ≥ 10 % m/m.
- Products already compliant with Regulation 648/2004 and placed on the market before 23 September 2029 may continue to be marketed indefinitely (Article 36(1)). Those placed on the market between 23 September 2029 and 22 September 2030 may be marketed only until 23 September 2030 (Article 36(2)).
- A significantly broader scope
Regulation 648/2004 focused its biodegradability requirements solely on surfactants. Regulation 2026/405 introduces, for the first time, targets for two categories of components not previously covered:
- Films and the polymers they contain must meet biodegradability criteria from 23 March 2032.
- Organic substances (other than surfactants or polymer films) that are intentionally added and present in a concentration of at least 10% of the product’s total mass must meet the biodegradability requirements by 23 March 2034.
These substances, other than surfactants, may persist in waste water and accumulate in the environment if they are not removed at wastewater treatment works. The 10% threshold is calculated on the basis of the total mass of the substances, excluding water, in order to ensure equal treatment between liquid and solid products and to avoid any dilution effect.
At an operational level, Article 4 of Regulation 2026/405 sets out this timeframe:
| Category | Part of Annex I | Criterion | Deadline |
| Surfactants and detergents containing them | Part A | Ultimate aerobic biodegradation | From the date of application of the Regulation, 23 September 2029 |
| Films or polymers contained in films | Part B | Criteria to be defined by the Commission | 23 March 2032 |
| Intentionally added organic substances (≥ 10 % w/w) | Part C | Criteria to be defined by the Commission | 23 March 2034 |
| Derogations for certain organic substances | Part D | — | Subject to conditions to be defined |
The European Commission is responsible for defining the relevant criteria and test methods using a phased approach, prioritising those components likely to have the most significant environmental impacts.
- Surfactants: a requirement unchanged, criteria revised
Regulation 2026/405 reaffirms the principle already set out in Regulation 648/2004: surfactants, and detergents containing them, must meet the criteria for ultimate aerobic biodegradation. Surfactants, whilst essential to the effectiveness of detergents, pose an environmental risk when released into sewerage systems or directly into surface waters.
The main change lies in the removal, in the new Regulation, of primary biodegradation as a component of the regulatory framework applicable to surfactants.
a. A definition being phased out
Regulation (EC) No 648/2004 defines, in Article 2(7) and (8), two distinct concepts:
- primary biodegradation: the structural transformation of the surfactant leading to the loss of its surface-active properties;
- ultimate aerobic biodegradation: the substance being completely used by micro-organisms, which break it down into carbon dioxide, water and mineral salts (mineralisation) and into new microbial cellular constituents (biomass).
Regulation 2026/405 no longer includes the definition of primary biodegradation in Article 2, nor does it set any compliance threshold for this parameter (which is 80% under Regulation 648/2004).
b. A single requirement: the mineralisation threshold
From 23 September 2029, all surfactants must directly meet the criterion for ultimate aerobic biodegradation in order to be placed on the market. The criteria remain set at 60% biodegradation within 28 days for methods based, in particular, on oxygen consumption or CO₂ production, and at 70% for methods based on the removal of dissolved organic carbon (DOC).
Two test conditions, which are already included in the current regulation but which are now mandatory in the absence of an alternative approach, deserve particular attention.
- No pre-adaptation of the inoculum: the inoculum, the mixture of microorganisms, often derived from sewage sludge, used to degrade the test substance, must not be exposed to the test substance prior to the start of the test. Tests must be carried out using microbial populations that have not been pre-exposed, in order to verify that the substance is truly degradable under realistic environmental conditions.
- No ‘10-day window’ rule: the test methods to be used (C.4-A to C.4-F) are the same as those employed by the OECD to screen for a substance’s ‘readily biodegradable’ properties. Normally, the substance must pass the threshold within 10 days of reaching 10% degradation; otherwise, it is deemed to have failed, even if it reaches 90% within 28 days. The Detergents Regulation adopts these same methods but explicitly excludes the 10-day window. Consequently, only the final result at 28 days matters, regardless of the rate of degradation.
These test conditions are not new: they are already set out in the current regulation and apply to ultimate biodegradation tests, regardless of the surfactant being tested. What has changed is the consequence of failing this test. Regulation 648/2004 still allows, for surfactants intended for detergents for industrial or institutional use, a derogation conditional upon demonstrating primary biodegradability and a supplementary risk assessment. This option will cease to exist with the removal of the requirement for primary biodegradability.
c. The repeal of the exemption system based on primary biodegradability
Under Regulation 648/2004, primary biodegradability acted as a ‘safety mechanism’: a manufacturer whose surfactant failed the ultimate aerobic biodegradation test could apply for an exemption, provided they demonstrated a level of primary biodegradation of at least 80%.
Regulation 2026/405 removes this systematic exemption route for surfactants. The phased approach is now reserved for the gradual inclusion of new components (films and high-concentration organic substances) within the scope of ultimate aerobic biodegradation, with deadlines set for 2032 and 2034. In the view of the European legislator, primary biodegradability does not provide sufficient environmental protection against persistent metabolites. The mineralisation threshold becomes the sole applicable requirement.
- A phased approach for new components
For polymer films and high-concentration organic substances, Regulation 2026/405 does not yet set out detailed technical criteria: it delegates this task to the European Commission, in accordance with a specific roadmap.
| Substance category | Biodegradability criteria | Test methods and conditions | Deadlines |
| Films and polymers (detergent capsules) | Criteria to be set by the Commission | Test methods to be defined by delegated acts | Criteria by March 2029; mandatory compliance by 23 March 2032 |
| Other organic substances intentionally added at ≥ 10 % m/m, excluding water | Criteria to be set by the Commission | Test methods to be defined by delegated acts | Criteria by March 2031; mandatory compliance by 23 March 2034, with possible derogations |
Article 34(1) of the Regulation also provides that, in its review report due by 23 March 2033 at the latest, the Commission must assess the feasibility of extending the biodegradability criteria to intentionally added organic substances present at concentrations below 10 %, or even of lowering this threshold. This review clause confirms the progressive nature of the text: the current requirements are only a first step, set to be strengthened over time.
- Requirements for testing laboratories
The Regulation maintains strict requirements regarding the qualification of laboratories carrying out biodegradability tests on surfactants. These laboratories must meet one of the following two conditions:
- comply with the principles of good laboratory practice (GLP), in accordance with Directive 2004/10/EC; or
- be accredited to the international standard ISO/IEC 17025, in accordance with Regulation (EC) No 765/2008.
These requirements ensure the consistency and reliability of test results across the EU, which is essential for effective market surveillance.
Key points
Regulation (EU) 2026/405 marks a turning point in the European approach to the biodegradability of detergents:
- It will apply only from 23 September 2029, with Regulation 648/2004 remaining in force until that date, followed by an extension of the scope beyond surfactants, with deadlines in 2032 (polymer films) and 2034 (organic substances ≥ 10%);
- Requirements restructured around a single criterion: the removal of primary biodegradability, with a single criterion of ultimate aerobic biodegradation for surfactants;
- Abolition of the historical exemption system based on primary biodegradability for surfactants;
- A phased regulatory approach, with technical criteria still to be defined by the Commission by 2029 and 2031, and a review clause opening the door to a future tightening of the 10% threshold.
For detergent manufacturers, their formulators and their suppliers of surfactants or polymers, the challenge is dual: to verify now that the available data on surfactants can demonstrate their compliance with the ultimate biodegradation criteria that will apply from 2029, and to anticipate future requirements concerning films, polymers and other organic substances used in formulations.The deadlines of 2029, 2031, 2032 and 2034 must already be integrated into the regulatory and R&D roadmaps of the companies involved.
Do you have any questions about the compliance of your surfactants, polymers or detergent formulations? Equitox can assist you in evaluating the available data, identifying any testing requirements and preparing for these new regulatory requirements.
Please do not hesitate to contact us at the following address: contact@equitox.eu.