Executive summary

Introduction and Regulatory Background

The European Union’s recast Drinking Water Directive (DWD, Directive (EU) 2020/2184) introduced harmonized requirements to ensure that materials in contact with drinking water do not compromise water quality. Adopted in 2020 in response to the “Right2Water” citizens’ initiative, the recast DWD raised water safety standards and mandated uniform rules for materials and products from the source to the tap. A key innovation is the establishment of European Positive Lists (EUPL) of authorized substances and materials: the DWD now requires that any substance, composition, or constituent used in drinking water contact materials must be approved and listed on a positive list. This ensures that all materials (e.g. pipes, coatings, fittings) meet the same safety criteria across the EU, facilitating free movement of goods while protecting public health. Article 11 of the DWD specifically called for EU-wide positive lists and the methods to develop them. By 12 January 2024, the European Commission was tasked to adopt common methodologies for testing and assessing substances for inclusion, and by 12 January 2025 to establish the first positive lists based on these methods. These measures were duly implemented through a series of Commission acts in April 2024, laying the groundwork for how new materials can be evaluated and added to the positive list.

The European Positive List (EUPL) for Drinking Water Materials

Under the DWD framework, European Positive Lists have been created for four broad categories of materials that come into contact with drinking water. These categories (each corresponding to an annex in the positive list legislation) are:

• Annex I – Organic Materials: e.g. plastics, rubbers, coatings and other carbon-based polymeric materials. (Notably, the list of authorized organic starting substances incorporates the existing EU food-contact plastics list from Regulation (EU) No. 10/2011.)
• Annex II – Metallic Materials: metals and alloys used for pipes, fittings, fixtures, etc. (Listed as compositions of metallic materials, often grouping allowable alloy compositions.)
• Annex III – Cementitious Materials: cement-based materials (such as concrete, mortar) and related additives.
• Annex IV – Enamel, Ceramic and Other Inorganic Materials: including glass, enamels, ceramics, and similar inorganic surfaces.

Each positive list entry is identified by a unique EUPL number (a 4-digit code) for tracking. The lists specify the authorized substances or compositions for use in manufacturing the respective material category. For example, Annex I (organic) contains monomers, additives, and other starting substances permitted in plastics or coatings, while Annex II (metallic) defines which alloy compositions are approved for use in contact with drinking water. Alongside the substance name or composition, the list may include conditions of use and migration limits. In particular, a Maximum Tolerable Concentration at the tap (MTCtap) can be set for certain substances or their reaction products – effectively a specific migration limit expressed as a concentration in drinking water.

Another crucial feature is that each listed entry has an expiry date. The initial positive lists use a set of standardized expiry dates (e.g. end of 2028, 2031, 2034, or 2037) assigned based on the substance’s hazard profile, the robustness of its risk assessment, and priority concerns (such as PFAS which were given earlier review dates). Before an entry’s expiry, a re-evaluation is required to keep it on the list. This mechanism ensures periodic review in light of updated science. If no review application is submitted by the deadline, the substance will be automatically removed from the list. Economic operators who wish to continue using a listed substance must support its review, and new data may be needed to renew the approval. Conversely, unlisted substances are not allowed for use in drinking water contact materials (once the EU rules fully apply), unless and until they go through the application process described in this paper. In summary, the EUPL serves as the exclusive “authorized menu” of ingredients for drinking water infrastructure materials, with built-in safeguards like usage conditions and expiry-based review to uphold safety over time.

Legal Framework and Key EU Instruments

The process for adding a new material to the positive list is defined by a set of legal acts that supplement the DWD. These include Commission Implementing Decisions that set technical rules and the initial lists, and Commission Delegated Regulations that establish procedural and administrative aspects. The key legal instruments are:

• Directive (EU) 2020/2184 (Drinking Water Directive, recast): The primary law requiring positive lists and empowering the Commission/ECHA to act. Article 11 of the DWD outlines the timeline and principles (e.g. requiring methodologies for testing/acceptance, creation of lists, and a procedure for applications). It also stipulates that applications for list inclusion/removal are to be submitted to the European Chemicals Agency (ECHA) and that the Commission will define the process via delegated acts.
• Commission Implementing Decision (EU) 2024/365: Adopted 23 Jan 2024, this decision lays down the methodologies for testing and accepting starting substances, compositions, and constituents to be included in the positive lists. Essentially, it provides the scientific and technical criteria for how substances should be tested (migration test conditions, etc.) and how risk assessments should be performed for the purposes of list inclusion. The decision contains several annexes detailing these methodologies (covering test methods, data requirements, toxicological evaluation criteria, etc., as later discussed).
• Commission Implementing Decision (EU) 2024/367: This decision establishes the first European Positive Lists of authorized substances for each material category. It compiles the initial Annex I–IV lists, largely derived from existing national positive lists and risk assessments that Member States submitted to ECHA in 2021. For example, the organic list in Annex I takes into account the EU food-contact plastics list as noted, and the metallic list in Annex II was built from compositions historically accepted in various countries. Decision 2024/367 is the reference point for knowing which substances are currently authorized.
• Commission Implementing Decision (EU) 2024/368: This complementary decision sets out the procedures and methods for testing and accepting final materials and products (made from the listed starting substances) at Member State level. It identifies parameters to test on final products (like turbidity, flavor/odor of water, color, microbial growth, unexpected substances leaching, etc.) and establishes pass/fail criteria for those tests. While this Decision is more about product conformity (rather than listing a substance), it is part of the overall hygiene requirements. It matters indirectly because even if a substance is on the positive list, the final article must still meet these material performance tests to be certified for use.
• Commission Delegated Regulation (EU) 2024/369: This is a crucial piece that lays down the procedure for including a new substance (or removing one) from the positive lists, including the format and information requirements for applications. It was adopted on 23 Jan 2024 under the mandate of DWD Article 11(5). Regulation 2024/369 specifies how an applicant should notify intent, prepare a dossier, and how ECHA and the Commission handle the application. In essence, it is the roadmap for anyone seeking to get a new organic or metallic material onto the EUPL.
• Commission Delegated Regulation (EU) 2024/370: This regulation establishes conformity assessment procedures for final products and the rules for designation of conformity assessment bodies (CABs). It details how products (e.g. a pipe or filter) are certified as compliant, which involves verifying they are made only from listed constituents and that they pass the tests in Decision 2024/368. While not directly about adding substances to the list, it’s part of the overall system ensuring that once substances are approved, products are properly tested and approved by notified bodies.
• Commission Delegated Regulation (EU) 2024/371: This sets out harmonized specifications for an EU marking of products in contact with drinking water. Similar to the CE marking concept, once a product passes conformity assessment, it will bear a special mark indicating compliance with the DWD hygiene requirements. Again, this is tangential to the listing of substances – but it’s a downstream step signifying that all components (substances, materials) and tests are in order.

All six acts were published on 23 April 2024 and enter into force on 15 May 2024. However, their application is phased in: the new harmonized system, including use of only the EU positive list substances and EU-wide product certification, becomes mandatory from 31 December 2026. Until the end of 2026, Member States’ existing national rules and approvals remain valid (allowing a transition period). Notably, any substances that were approved at national level after the initial list compilation (i.e. between July 2021 and the end of 2026) may continue to be used domestically until 31 December 2032 even if not yet on the EU list. This gives a grace period for those recent national authorizations while industry or authorities work to get them onto the EU positive list. From 2027 onward, any new material must go through the EU procedure via ECHA – making the following process highly relevant.

With this legal foundation in place, the next sections detail the step-by-step procedure to get a new organic or metallic material onto the EUPL, along with the technical and scientific requirements at each step.

Procedure for Adding a New Material to the EUPL

Getting a new substance or material composition listed involves a multi-stage process overseen by ECHA and the European Commission. The journey can be outlined in several key steps, from initial notification to final Commission decision:

1. Notification of Intention (Pre-Application Stage)

Prospective applicants must begin by notifying ECHA of their intention to submit an application, well in advance of the application itself. According to the procedure in Delegated Regulation 2024/369, this notification of intent must be made at least 12 months before the actual dossier submission. In practice, ECHA will start accepting “notifications of intention” from 31 December 2025 onward (one year before the system’s 2026 start date). The intention notification is a relatively simple step – the applicant provides basic information on the substance or material they plan to apply for, and an expected submission timeline.

The rationale for this advance notice is to allow ECHA to plan resources and to promote collaboration. Once an intention is received, ECHA publishes it on their website. This public posting is meant to alert other interested parties (e.g. multiple companies using the same substance) so they can possibly form a consortium or submit a joint application. By pooling efforts into a single dossier, applicants can avoid duplicate testing (particularly animal studies) and share costs. Joint submissions are strongly encouraged; Recital 2 of Regulation 2024/369 explicitly notes that grouping efforts for the same substance and preventing unnecessary animal tests is a priority. In essence, if “Company A” notifies intent to list a new coating additive, “Company B” considering a similar application can see that and ideally they would cooperate instead of submitting separate dossiers. ECHA may facilitate contact between such parties.

The notification of intention itself does not involve a full data package – it’s more a signal. However, it is a binding step in that once notified, the applicant is expected to deliver the full application within the next 12 months. If they fail to submit in that window, the process might require a fresh notification. In summary, the first milestone is planning: letting regulators know of your upcoming application and opening the door for collaboration.

2. Preparation and Submission of the Application Dossier

After notifying intent, the applicant proceeds to prepare the comprehensive application dossier. This is the core submission that contains all data and justifications for why the new substance or material should be added to the positive list. The DWD Guidance Volume IV (not detailed here) provides specific advice on dossier format, and Regulation 2024/369 (Annex) legally specifies the information requirements. At a high level, the application must include “all necessary information to assess the application” in accordance with the common testing and acceptance methodologies. In practice, the dossier is compiled using ECHA’s IUCLID software, the same electronic format used for REACH chemical registrations, ensuring a structured submission (sections for substance identity, hazard data, etc.). Notably, at this time no application fee is being charged by ECHA for DWD positive list submissions, which lowers the barrier for applicants (this could be revisited in the future, but currently the EU covers the costs).

Data Requirements: The application needs to be very robust. Key components of the dossier typically include:

• Applicant and Substance Identification: Details of the applicant (company/association or authority) and the substance or composition in question. This includes chemical name, CAS/EC numbers if applicable, and for mixtures or alloys a description of the composition. For a new organic substance, one would provide its molecular structure, purity grade and significant impurities, and possibly the manufacturing method (especially if it influences impurity profile). For a new metallic material, the dossier would describe the alloy’s constituent metals (percentages) and any relevant material specifications (e.g. a standard grade of stainless steel or a novel alloy formulation). If the application is for a group of substances (group entry), this needs clear definition and justification.
• Intended Use and Function: A description of how and where the substance will be used in drinking water systems. For instance, is it a monomer used to make a new polymer pipe, an additive in a plastic coating, or an alloy used for taps? The dossier should specify the material category (organic, metallic, etc.) and the role of the substance (e.g. “cross-linker in epoxy lining” or “copper-zinc alloy for fittings”). Any conditions of use anticipated should be stated, such as maximum percentage in a formulation, or if it’s only for cold water applications, etc. This contextual information is crucial for risk assessment because it frames the exposure scenario.
• Existing Evaluations or Approvals: If the substance has been previously assessed (by a Member State authority, by EFSA for food contact, or by another regulatory body), those findings should be included. For example, many organic substances might already appear on national positive lists or in the EU food contact list – those risk assessments can be referenced to support the application. The DWD positive list for organics explicitly draws from the food-contact plastics list, so demonstrating alignment with such existing approvals can be advantageous.
• Migration Testing Data: A centerpiece of the dossier is the experimental data on how much of the substance (and its relevant by-products) can migrate or leach into water. The applicant must perform migration tests according to the standardized methods (discussed in the next section on testing) and provide the full results. This includes descriptions of the test setup, conditions (surface area to volume ratio, water type, temperature, duration), and the measured concentrations of the substance (and any other chemicals detected) in the water over the test periods. For organic substances, there may be multiple test cycles (to see declining migration), and for metals, often a lengthy rig test. The data should identify the worst-case concentration that could appear in drinking water. All relevant analytical method details and validation information should be provided, since the reliability and sensitivity of the analysis (e.g. detection limits) are critical when dealing with very low concentration limits. According to the guidance and Regulation, a full study report for each migration test (complying with GLP and relevant EN standards) must be included, and the report must clearly state adherence to the prescribed methods. This assures regulators that the testing was done correctly.
• Identification of “Relevant Chemical Species”: Alongside raw test data, the dossier needs to list the chemical entities that are considered in the risk assessment. The term “relevant chemical species” is used in the DWD context to mean any substance that originates from the starting material and could pose a health risk or contribute to exposure. This can include the original substance applied for, known impurities or residual monomers, reaction by-products, breakdown products, or non-intentionally added substances (NIAS) that were detected in migration tests. Essentially, if something leaches into the water (or is suspected to, based on chemistry) and is not obviously innocuous, it should be treated as a relevant species. The applicant must rationalize which species are relevant and need toxicological evaluation. For example, a new polymer additive might contain a small fraction of unreacted monomer; both the additive and the monomer (if leachable) would be “relevant species” to assess. ECHA’s methodology (Annex IV of Decision 2024/365) provides criteria for identifying relevant species (e.g. any leachable that is toxicologically concerning or present above certain levels).
• Toxicological Data and Risk Assessment: The application must include a thorough toxicological profile for each relevant chemical species, along with a risk assessment demonstrating that their presence in water would be safe. This will be elaborated in a dedicated section below (on risk assessment methodology), but in summary, applicants should provide all available hazard data (from studies or literature) covering acute and chronic toxicity endpoints, as well as special endpoints like genotoxicity, carcinogenicity, reproductive toxicity, etc., for each substance. If new studies have been conducted (for example, to fill a data gap for this application), full reports or robust study summaries are needed. Using those hazard data, the applicant must derive acceptable concentration limits (MTCtap) and compare them to the expected exposure (the migration levels). The risk assessment report in the dossier should clearly show that under the worst-case conditions, the concentration in drinking water (Ctap) remains below the safe threshold (MTCtap) for each species. Any proposed risk management measures (like restricting use or specifying an MTCtap value) that the applicant suggests can also be part of this section. Annex V of Decision 2024/365 outlines in detail what toxicological information is expected based on the level of exposure; for instance, higher migration levels demand more comprehensive tox data, whereas extremely low migration might allow a reduced data set. The applicant should follow these requirements closely.
• Proposal for Listing (Entry Details): Finally, the applicant may propose the specifics for how the substance should appear on the positive list. This means indicating under which Annex (material category) it falls, the name or description (for metals, possibly a group entry for an alloy family), any conditions of use (e.g. “for use up to X% in polyethene”, or “not for hot water use”, etc.), and any suggested migration limit or MTCtap value if applicable. They might also suggest an appropriate expiry date category, though the final decision on expiry will be by authorities. If the applicant foresees that the substance has borderline safety or limited data, they might anticipate a shorter review cycle (so an expiry sooner) and indicate ongoing studies that will be delivered at renewal.

Compiling this dossier is typically the most resource-intensive part for the applicant. It can take many months or even years of preparation (generating data, performing tests, writing risk assessments). Once ready, the application is formally submitted to ECHA. All submissions are electronic through ECHA’s IT portal. Upon receipt, ECHA will perform an initial completeness check to ensure all required elements are present (similar to how REACH dossiers are handled). If something essential is missing (for example, a toxicological endpoint evaluation or the migration test report), ECHA can deem the application not valid and ask for additional information before proceeding.

One important note: the window for submitting applications begins 31 December 2026 (when the EU positive list system becomes operational). No new-substance applications will be accepted before then; until that date, substances must be dealt with under national regimes. After that, any stakeholder aiming to introduce a new material must use this EU procedure.

3. ECHA’s Evaluation and Risk Assessment Review

Once a complete application is accepted by ECHA, the evaluation phase begins. ECHA, in cooperation with Member States, plays a central role in the scientific assessment:

• Publication and Consultation: ECHA will publish information about the application on its website (while respecting confidentiality for any trade secrets). This publication typically includes the name of the substance or material, the intended use, and perhaps a summary of the dossier (excluding confidential business information). At the same time, ECHA invites third parties to submit any relevant scientific data or comments within a specified period. This is analogous to public consultations held for other chemical evaluations. Interested parties could be other companies, researchers, NGOs, or Member State authorities who might have information on the substance’s effects or presence. For example, if an NGO has done research on a certain chemical showing it has endocrine effects, they could submit that. Or if a Member State is aware of regional concerns or has done testing, they can contribute. This step ensures transparency and that ECHA can gather all available information beyond what the applicant provided.
• Committee for Risk Assessment (RAC) Involvement: ECHA’s Committee for Risk Assessment (RAC) – the same body that handles REACH and CLP opinions – is charged with evaluating the application from a human health risk perspective. RAC will likely form a working group or rapporteur for DWD positive list dossiers, given the specialized nature. They will scrutinize the applicant’s data, the methods used, and the conclusions drawn. Key tasks include verifying the toxicological assessment (e.g. were proper uncertainty factors applied to derive the MTCtap? Are all relevant health endpoints considered?) and verifying the exposure assessment (e.g. is the estimated Ctap realistic and based on worst-case as required?). They will check compliance with the methodology from Decision 2024/365 and Guidance Volumes I & II. If needed, RAC can ask the applicant, via ECHA, for clarifications or additional data. For instance, RAC might query if a particular metabolite was considered, or request further justification for waiving a certain toxicological study. The process is interactive to ensure a thorough review.
• Scientific Opinion: After evaluation, RAC will formulate an opinion on the application. This opinion addresses whether the substance or material, under the proposed conditions of use, meets the safety criteria of Article 11(1) DWD– essentially that it will not endanger human health or the quality of water. The opinion will state whether the substance should be included in the positive list and under what conditions. There are a few possible outcomes:
  • Positive Opinion: RAC concludes the substance is safe as proposed. They will likely affirm an MTCtap value (or say that migration levels are negligible), and may agree with any conditions or suggest minor ones.
  • Positive with Conditions: RAC finds the substance can be safe only with certain restrictions. They might recommend setting a specific migration limit in the listing, or limiting the material’s use (e.g. “only in cement at up to 1%” or “not to be used in contact with soft water below pH 6” if corrosion is a factor). These conditions aim to ensure Ctap remains below MTCtap in all cases. RAC could also recommend a shorter expiry review period if they feel data is preliminary (for example, “list with expiry in 5 years instead of 15 to obtain more data”).
  • Negative Opinion: RAC is not convinced of safety – perhaps the toxicological data revealed a concern (like a genotoxic potential that cannot be thresholded), or the migration was too high relative to safe intake, or important data are missing. In this case, RAC would advise against listing the substance (at least until certain issues are resolved).

Importantly, RAC’s opinion is not the final decision – but it carries significant weight. The DWD mandates that the Commission take ECHA’s scientific opinions into account when updating the lists. Also, as per Regulation 2024/369, the Commission itself can request RAC to evaluate substances (for example, if a Member State wants a removal, the Commission can task RAC even without an industry application). In our context, after an industry application, RAC’s completed opinion is forwarded to the European Commission and made publicly available. This whole evaluation stage is typically expected to be completed within a set timeframe (often around 9 to 12 months after application validation, although this can vary with complexity).

4. Commission Decision and Inclusion in the Positive List

With RAC’s opinion in hand (and all supporting documentation), the process moves back to the policy arena for a final decision. The steps are:

• Drafting the Inclusion Proposal: The European Commission (specifically DG Environment, which handles drinking water policy, in liaison with DG GROW for internal market aspects) will draft a proposal to amend the positive list. If the opinion was positive, this draft will add a new entry under the appropriate Annex of Implementing Decision 2024/367 (or a future consolidated act). The draft will specify the substance name/composition, an assigned EUPL number, and any conditions or limits as recommended. For example, it might read: “EUPL No. 1234 – [Chemical name] – for use as a starting substance in organic materials [plastics] – MTCtap = 0.01 mg/L; Specific conditions: not to exceed 5% w/w in final product; expiry 31/12/2034.” If RAC gave conditions, the Commission usually follows them, possibly with some adjustments after consulting Member States. If the opinion was negative, the Commission would draft a decision to reject the application, meaning no change to the list (or potentially to remove an entry in case of a removal application).
• Member State Committee Procedure: The amendment of the positive list is done via an Implementing Act under the comitology examination procedure (since Article 11(2) DWD called for implementing acts for the lists). This means the draft decision is presented to the Standing Committee on Drinking Water (or a similar committee of Member State representatives). Member States discuss and then vote on the proposal. Given that by this stage a scientific review has occurred, Member State debates usually focus on any national implications, transitional measures, or ensuring the wording of conditions is enforceable. If the majority vote is positive, the Commission can formally adopt the Decision. (If they vote against, revisions or an appeal might be needed, but for individual substances this is rare unless there’s controversy.)
• Publication and Entry into Force: The Commission Implementing Decision to update the EUPL is published in the Official Journal of the EU. The new substance is thereby officially added to the European Positive List, effective on the date specified (often 20 days after publication, or sometimes immediately if urgency is noted). The ECHA online database of positive list entries will also be updated accordingly, allowing stakeholders to search and find the new listing in a user-friendly way (though the legal reference remains the OJ publication).

Once included, the substance or material can be used by manufacturers across the EU for drinking water applications, subject to any conditions in its listing. National authorities can no longer object to its use on national grounds related to health (harmonization effect), and any product containing it just needs to go through the normal product conformity route (which confirms the product is made of listed substances and passes the final tests).

It’s worth noting that the new entry will have an expiry date assigned, as discussed. For a brand-new substance, regulators might choose a relatively short initial expiry (e.g. 5 years) if the dataset had some uncertainties, to ensure a prompt re-evaluation with more data. Substances with very comprehensive data and low risk might get the maximum initial period (15 years or so). Either way, the applicant and other stakeholders should plan for the review application prior to expiry to maintain continuity (the review process is essentially a similar application but focused on updating any new data since the last review).

If the Commission’s decision was instead a rejection (following a negative RAC opinion), the substance cannot be used in the EU for drinking water contact (unless it was already on a national list and still in transition, but post-2026 that scenario fades out). The applicant might then consider generating new data and trying again, but there may also be a provision for an appeal or re-submission if substantive new evidence arises.