Water
Drinking Water Directive 2020/2184 (DWD)
Directive (EU) 2020/2184 of the European Parliament and of the Council of 16 December 2020 on the quality of water intended for human consumption (recast) seeks to introduce revised rules to protect human health from the contamination of water intended for human consumption by ensuring that it is ‘wholesome and clean’, It also seeks to introduce hygienic requirements for materials in contact with drinking water, such as pipes, as well as:
- improve access to water intended for human consumption;
- introduce a cost-effective risk-based approach to monitoring water quality.
Water intended for human consumption is defined as: all water, either in its original state or after treatment, intended for drinking, cooking, food preparation or other domestic purposes in both public and private premises, regardless of its origin and whether it is supplied from a distribution network, supplied from a tanker or put into bottles or containers, including spring waters; all water used in any food business for the manufacture, processing, preservation or marketing of products or substances intended for human consumption. The directive does not apply to natural mineral waters (but not spring water) as referred to in Directive 2009/54/EC.
Water-quality standards: EU countries must ensure that water intended for human consumption is ‘wholesome and clean’. It must be free from any micro-organisms and parasites and from any substances which, in numbers or concentrations, are a potential danger to human health. It must meet specified minimum requirements.
PFAS metrics under the DWD
Directive 2020/2184 (DWD) (recast) which entered into force on 12 January 2021, introduced parameters and parametric values for per- and polyfluoroalkyl substances (PFAS). These values are 0.5 μg/l (500 ng/l) for the ‘PFAS Total’ parameter and 0.1 μg/l (100 ng/l) for the ‘Sum of PFAS’ parameter, which covers a list of 20 PFAS. Member States are required to comply with these parameters by 12 January 2026(4). They may incl
PFAS Total: 0.50 μg/l (500 ng/l) [DWD Annex I Part B] means the totality of per- and polyfluoroalkyl substances. This parametric value shall only apply once technical guidelines for monitoring this parameter are developed in accordance with Article 13(7). Member States may then decide to use either one or both of the parameters ‘PFAS Total’ or ‘Sum of PFAS’.
Sum of PFAS: 0.10 μg/l (100 ng/l) [DWD Annex I Part B] means the sum of per- and polyfluoroalkyl substances considered a concern as regards water intended for human consumption listed in point 3 of Part B of Annex III. This is a subset of ‘PFAS Total’ substances that contain a perfluoroalkyl moiety with three or more carbons (i.e. –CnF2n–, n ≥ 3) or a perfluoroalkylether moiety with two or more carbons (i. e. –CnF2nOCmF2m–, n and m ≥ 1). Note: Sum of PFAS does not include TFA.
PFAS Total and TFA
Extracts from Commission Notice Technical guidelines regarding methods of analysis for monitoring of per- and polyfluoroalkyl substances (PFAS) in water intended for human consumption (C/2024/4910) 7.8.2024
The range of substances included in the ‘PFAS Total’ parameter is defined in the Directive as ‘the totality of per- and polyfluoroalkyl substances’. The Directive does not provide a more specific definition of the parameter.
The only broadly agreed upon definition of PFAS available when the Directive was adopted was the 2018 OECD technical definition [1]. That definition was revised in 2021, i.e. after the adoption of the Directive [2]; it now includes the substance trifluoroacetic acid (TFA). TFA, an ultrashort-chain PFAS, is a hydrophilic, mobile and persistent substance that also occurs naturally in the environment, Man-made TFA primarily enters the water cycle through the degradation of various fluorochemicals and from diffuse contamination sources. There are a lot of different possible sources of TFA in raw water sources including pesticides, refrigerants, medicinal products, sewage treatment and industrial activities.
The available TFA monitoring results from raw water sources across the Member States indicate that TFA concentrations at the point of compliance may significantly exceed the Directive’s ‘PFAS Total’ parametric value.
The health effects of TFA are currently being assessed by the World Health Organization (WHO) on the basis of the most recent scientific knowledge. Depending on the results of this assessment, the WHO could issue new recommendations regarding TFA concentrations in drinking water.
This technical guidance includes recommendations on how to deal with TFA under the parameter ‘PFAS Total’.
Lastly, in 2024 the European Commission also published technical guidelines regarding methods of analysis for monitoring of PFAS in water intended for human consumption.
[1] OECD (2018): TOWARD A NEW COMPREHENSIVE GLOBAL DATABASE OF PER- AND POLYFLUOROALKYL SUBSTANCES (PFASs): Summary report on updating the OECD 2007 list of per- and polyfluoroalkyl substances. Edited by OECD Publishing. Paris (OECD Series on Risk Management, 39).
[2] OECD (2021): Reconciling Terminology of the Universe of Per- and Polyfluoroalkyl Substances: Recommendations and Practical Guidance. Edited by OECD Publishing. Paris (OECD Series on Risk Management, 61).
Section 4.2.2 Analytical reporting of ‘PFAS Total’. For the analytical reporting of the results of ‘PFAS Total’, the contribution of the ultrashort-chain PFAS TFA in water intended for human consumption should be evaluated, as the TFA concentration could (significantly) exceed the Directive parametric value of ‘PFAS Total’. The Commission recommends an approach for reporting analytical results of ‘PFAS Total’ including “The analytical report includes the reporting of [PFAS Total], [TFA] and [PFAS Total] – [TFA], indicating which proxy method and targeted method have been used.”
Explanatory note 1: Measuring ‘PFAS Total’ has proved highly challenging. The Commission’s Technical guidelines regarding methods of analysis for monitoring of PFAS in water intended for human consumption state that there is currently no analytical method that can accurately quantify the ‘PFAS Total’ parameter. While the guidelines fall back on three possible “proxy” methods, they also state that if the amount resulting from one of these methods is smaller than the TFA concentration (measured separately), then the overall result should be reported as “inconclusive”.
Explanatory note 2: A study is underway (by the WHO, commissioned by DG Environment) to support a review and possible revision (in 2026) of the PFAS standards in the DWD.
Guidance and limit values for TFA in drinking water
Some member states have set guidance/guideline or limit value for TFA in drinking water. These are derived from available data.
Germany
The German drinking water guidance value or German Health Orientation Value (GOW) for TFA has evolved and increased as more TFA toxicity data has become available, with the German Environment Agency (UBA) most recently increasing the allowable guidance limit in 2020 [1]. The GOW was determined from a chronic (long term – 1 year) drinking water study in rats that were exposed to high concentrations of TFA (between 100,000 and 2 million times higher than the average concentration found in rainwater in 2018-2019). No treatment-related adverse effects were found at any dose that was used in this study and the no-observed-adverse-effect-level (NOAEL) was determined to be the highest concentration tested. In their derivation of the GOW, UBA calculated a tolerable daily intake (TDI) value by applying a safety factor of 100 to the lowest dose used in the aforementioned study. The GOW was then set by taking into account a standard human body weight and human daily water consumption and then adding an additional safety factor of 10 to allow TFA from drinking water to contribute a maximum of 10% to the tolerable daily intake (TDI) of TFA.
The GOW for TFA is 60 µg/L in drinking water, with a target value of 10 μg/L. Rainwater collected in eight locations across Germany in 2018–2019 showed 0.335 µg/L as the precipitation-weighted mean concentration of TFA [2], approximately 200 times lower than the GOW. The average concentration of TFA measured in the Atlantic Ocean in 2022/23 is about 0.3 µg/L [3].
[1] Trifluoressigsäure (TFA)–Gewässerschutz im Spannungsfeld von toxikologischem Leitwert, Trinkwasserhygiene und Eintragsminimierung. Erläuterungen zur Einordnung des neuen Trinkwasserleitwerts von 60 μg/L. 20. Oktober 2020. Umweltbundesamt www.umweltbundesamt.de
[2] UBA Final report Persistent degradation products of halogenated refrigerants and blowing agents in the environment: type, environmental concentrations, and fate with particular regard to new halogenated substitutes with low global warming potential | Umweltbundesamt; https://www.umweltbundesamt.de/publikationen/persistent-degradation-products-of-halogenated
[3] TEXTE 35/2024 Projektnummer 172963FB001431 Untersuchung von aktuellen Meerwasserproben auf Trifluoressigsäure. Finnian Freeling, Anna Mangels Im Auftrag des Umweltbundesamtes, TEXTE 35/2024 Examination of current seawater samples for trifluoroacetic acid | Federal Environment Agency (umweltbundesamt.de)
Netherlands
Netherlands has an indicative drinking water guideline value for TFA of 2.2 μg/L (2,200 ng/L). The indicative drinking water guideline value of 2200 ng/L applies if only TFA is present in the sample in question. However, PFAS, including TFA, almost never occur as a separate substance, but usually in mixtures with different PFAS. The expectation is that all PFAS work in a similar way and contribute to the total toxicity of the mixture. That is why the RIVM advises to include all PFAS present in a sample in a risk assessment, taking into account the differences in potency between the individual PFAS. In view of the mixture effects of PFAS, a national policy-based drinking water guideline value of 4.4 ng/L applies for the sum of PFAS, expressed as PFOA equivalents (PEQ). To calculate the PEQ, the concentration of an individual PFAS is multiplied by the associated Relative Potency Factor (RPF). The indicative drinking water guideline value of 2200 ng TFA/L is derived on the basis of the above-mentioned drinking water guideline value of 4.4 ng PEQ/L, taking into account the relative potency factor (RPF) of TFA compared to PFOA (RPF 0.002). As stated, the value of 2200 ng/L only applies if only TFA is present in the sample in question. If TFA is found together with other PFAS, the concentrations of individual PFAS must be added, after correction for potency using RPFs. The summed concentration (sum-PEQ) can then be compared with the drinking water guideline value of 4.4 ng PEQ/L. Extract from RIVM document 11 March 2023.
A detailed RIVM report RIVM-VSP Advice 14434A02 – Drinking water guideline value for trifluoroacetic acid, 2022 sets out how the guidance value is derived.
Denmark
Denmark has set a binding and health-derived limit value for TFA in drinking water at 9μg/L. See BEK nr 810 of 18/06/2024 Executive Order on Water Quality and Supervision of Water Supply Facilities Annex 1, d Quality requirements for nationally determined chemical parameters (precautionary and aesthetic considerations). Unless otherwise stated, the table refers to maximum permissible values. When assessing whether quality requirements are met, the measurement uncertainty must not be used as extra tolerance. Quality requirements for consumer taps TFA 9μg/L.
Austria
In Austria, TFA was analysed in groundwater as part of water status monitoring (GZÜV). TFA is widely detectable in groundwater in Austria. TFA was found in all samples from risk-based selected groundwater monitoring sites. The average TFA concentration is 0.71 µg/l, the maximum value is 7.0 µg/l. 75% of all samples showed concentrations below 0.81 µg/l TFA(Water Quality in Austria – Annual Report 2018-2020). AGES will investigate TFA in drinking water in 2025 as part of an Austria-wide monitoring programme. AGES- Austrian Agency for Health and Food Safety (AGES) is a company owned by the Republic of Austria.
https://www.ages.at/en/human/nutrition-food/residues-contaminants-from-a-to-z/trifluoroacetic-acid#c29153
Water Framework Directive 2000/60/EC
Citizens, nature and industry all need healthy rivers and lakes, groundwater and bathing waters. The Water Framework Directive (WFD) focuses on ensuring good qualitative and quantitative health, i.e. on reducing and removing pollution and on ensuring that there is enough water to support wildlife at the same time as human needs. Since 2000, the WFD has been the main law for water protection in Europe. It applies to inland, transitional and coastal surface waters as well as groundwaters. It ensures an integrated approach to water management, respecting the integrity of whole ecosystems, including by regulating individual pollutants and setting corresponding regulatory standards. It is based on a river basin district approach to make sure that neighbouring countries cooperate to manage the rivers and other bodies of water they share.
The Water Framework Directive (WFD) is the primary legislation. It is supported by two so-called daughter directives on the quality and quantity of groundwater and on the quality of surface water. The WFD contains provisions regarding the deadlines for meeting the objectives of the Directive, as well as provisions on exemptions. The annexes to the WFD specify details as regards, for example, monitoring requirements, the criteria for assessing water body status, and the contents of the River Basin Management Plans (RBMPs).
At present, the WFD includes in its Annex X the list of priority substances that Member States must monitor in surface waters, but the standards for them are set in the Environmental Quality Standards Directive (EQSD) and must be met to achieve good surface water chemical status in accordance with WFD Article 4 and Annex V point 1.4.3. The WFD also requires Member States to set and meet Environmental Quality Standards (EQS) for substances of national concern, i.e. river basin specific pollutants; the monitoring of which currently contributes to the assessment of ecological status. This list of priority substances needs to be reviewed, and updated if necessary, every 6 years.
Similarly, the list of pollutants and standards of EU-wide concern in Annex I to the Groundwater Directive (GWD) must also be reviewed every 6 years; these contribute to the assessment of chemical status in groundwater. That Directive also complements the WFD by including requirements as regards pollutant trends and quantitative status.
PFAS
Article 16 of the Water Framework Directive (WFD, 2000/60/EC) requires the Commission to identify Priority Substances among those presenting significant risk to or via the aquatic environment, and to set EU Environmental Quality Standards (EQS) for those substances in water, sediment and/or biota.
The current position for PFAS in surface water is summarised in a Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) March 2025 document Opinion on “Draft Environmental Quality Standards for PFAS total under the Water Framework Directive” – PFAS.
PFAS SCHEER opinion on EQS for PFAS
The SCHEER is of the opinion that there is insufficient data to derive an (E)QS for PFAS total in line with the technical guidance document (TGD). SCHEER would recommend that Relative Potency Factor (RPF) approaches be used. The SCHEER advises that the RPF approach should be extended as rapidly as possible to include any other individual PFAS as up to 100 individual PFASs can be determined reliably. The eco- and toxicity data should be generated as soon as possible for these additional compounds. The SCHEER recommends that the important missing information should be generated with the support of the European Commission.
TFA SCHEER opinion on TFA
The SCHEER notes the large overlap in known health effects of TFA (liver metabolism and liver weight) that results in a cumulative effect with the other 24 PFAS in this chemical group. Therefore, The SCHEER would recommend adopting the RIVM advice and, thus, adding TFA to the list of 24 PFAS. The potency of TFA is clearly less than the other PFASs of the list. The SCHEER would agree with the 0.002 RPF calculated by RIVM (see explanatory note). The SCHEER is aware of the ongoing CLH process under CLP (Classification, Labelling and Packaging) Regulation led by the German Competent Authorities to classify TFA as reprotoxic 1B, but the scientific evidence supporting this intention, as well as the proposal for harmonized classification, is not yet available. Therefore, the SCHEER is currently not in the position to conclude whether the classification of TFA as reprotoxic 1B would have any consequences for its RPF.
Explanatory note: see RIVM report RIVM-VSP Advice 14434A02 – Drinking water guideline value for trifluoroacetic acid, 2022