What is conformity assessment and the NLF
Under the Drinking Water Directive (DWD), all products and materials in contact with drinking water must undergo a conformity assessment before being placed on the EU market. This system underpins the entire DWD framework and makes it possible for there to be one harmonised EU market for products and final materials.
Conformity assessment is the formal process of demonstrating that your product meets EU legal requirements — for DWD this means compliance with hygiene rules, migration limits, and the European Positive Lists. At the end of this process, you receive a certificate from a Notified Body, issue an EU Declaration of Conformity, and apply the Drinking Water Compliance Mark (DWCM). Note that unlike the CE mark used in other sectors, the CE mark does not apply to DWD.
The Basics of the New Legislative Framework (NLF)
The DWD system is built on the EU’s New Legislative Framework (NLF), which provides a common approach across many EU product laws. The NLF defines:
- Modules: the different routes for conformity assessment (Module B, C, D).
- Notified Bodies: independent organisations designated by Member States to carry out assessments.
- Manufacturer obligations: technical files, declarations of conformity, and correct product marking.
If you are familiar with CE marking under other EU legislation, the structure under the DWD will feel very similar. For example, if you already work with the CPR or other NLF-based legislation, the DWD system will feel familiar. The DWD adopts the Modules verbatim from Decision 768/2008 — meaning no additional DWD-specific deviations.
Two further EU documents are essential for understanding how conformity assessment works in practice:
- The Blue Guide on the Implementation of EU Product Rules — the Commission’s main guidance on how the NLF works, covering roles of manufacturers, importers, distributors, technical documentation, and product compliance.
- Regulation (EU) 2019/1020 on Market Surveillance and Compliance of Products — binding EU law that governs how Member States enforce product rules, inspect documentation, and ensure that only compliant products remain on the market.
Which Modules Apply in the DWD?
For drinking water products, only a limited set of NLF modules are used:
- Module B: EU-type examination (testing and approval of a representative sample).
- Module C: Conformity to type based on production verification.
- Module D: Conformity to type based on production quality assurance.
- High-risk products (RG1, RG2) → Module B + D.
- Lower-risk products (RG3, RG4) → Module B + C.
What Manufacturers Must Do
For companies used to national approval systems, the DWD conformity process may look unfamiliar at first — but in practice it follows a clear, predictable sequence. The exact depth of testing and certification depends on the risk group of the product.
The essentials are:
- Classify your product correctly: determine the product group and risk group under CID (EU) 2024/368. This defines the required testing and conformity route.
- Carry out the required testing: arrange migration testing in line with the European test methods in the implementing acts.
- Work with a Notified Body: undergo the correct conformity assessment procedure (Module B + C for lower risk, Module B + D for higher risk).
- Prepare your technical file: keep test reports, formulation details, certificates, production controls, and all required documentation for market surveillance authorities.
- Issue your Declaration of Conformity: formally declare that the product is compliant with the DWD requirements.
- Apply the DWD marking: mark your product with the Drinking Water Compliance Mark (DWCM), allowing EU-wide market access.
While this is a simplified overview, the system is straightforward once classification and testing are correctly established. The main task for manufacturers is ensuring the right product classification and risk group from the start so the correct conformity module is followed.