Focus on Directive (EU) 2026/805: Revision of Water Quality Standards and Monitoring Mechanisms

Introduction: a new framework for the “Zero Pollution” ambition

Directive (EU) 2026/805 of 30 March 2026 constitutes a major revision of the European Union’s water legislation. By simultaneously amending the Water Framework Directive (2000/60/EC), the Groundwater Directive (2006/118/EC), and the Environmental Quality Standards Directive (2008/105/EC), the text aims to align the protection of water resources with the European Green Deal’s “zero pollution” ambition.

The urgency of this reform is highlighted by findings from the European Environment Agency (EEA). According to Recital 3 of Directive (EU) 2026/805, which refers to the EEA’s 2024 report, Member States reported that, in 2021, approximately 40% of surface water bodies had achieved good or high ecological status, while 38% had achieved good chemical status. This situation is often obscured by historical contamination or by the emergence of new pollution issues.

1. Revision of the assessment of chemical and ecological status

The Directive introduces a fundamental change in the way water quality is assessed and classified.

A. Integration of river basin-specific pollutants

The most significant technical innovation is the transfer of river basin-specific pollutants into the definition of the “good chemical status” of surface waters.

Previously, these pollutants were considered physicochemical quality elements supporting the assessment of ecological status. From now on, for a water body to achieve good chemical status, it must comply not only with the environmental quality standards (EQSs) established for Union priority substances, but also with the EQSs applicable to river basin-specific pollutants identified at national or regional level.

Certain substances, such as alachlor, atrazine, and simazine, which no longer pose a widespread risk at Union level, have been moved from the list of priority substances to a register of harmonized EQSs for river basin-specific pollutants.

B. New definition of status deterioration

The Directive clarifies the concept of “deterioration of status”, drawing on the case law of the Court of Justice of the European Union.

Any deterioration by at least one class of an individual quality element—whether biological, chemical, or hydromorphological—is now considered to constitute deterioration, even where it does not result in a reduction in the overall classification of the water body.

C. Categorization of priority substances

The revised Directive (EU) 2026/805 introduces a more targeted and proportionate approach to the management of priority substances in aquatic environments. As part of the review of the list of priority substances, the European Commission now classifies these substances into three distinct categories, each reflecting specific environmental concerns and triggering tailored regulatory obligations for Member States and industrial operators.

D. Priority Hazardous Substances (PHS)

These substances pose a particularly high risk to the aquatic environment and, in some cases, to human health. Their classification entails stringent measures aimed at reducing their presence in water bodies at the source. Member States are required to implement actions to cease or progressively eliminate discharges, emissions and losses of these substances.

The Directive establishes an ambitious objective: the complete phase-out of releases no later than 20 years after the substance has been designated as a Priority Hazardous Substance at Union level. Newly classified PHS include Bisphenol A (BPA), reflecting increasing concerns regarding its ecotoxicological effects and endocrine-disrupting properties.

For industrial operators, this classification may result in stricter emission controls, tighter permit conditions under environmental legislation, implementation of best available techniques (BAT), and, where feasible, substitution of hazardous substances by safer alternatives. Companies using or releasing PHS may also face increased monitoring and reporting obligations.

E. Substances behaving as ubiquitous Persistent, Bioaccumulative and Toxic substances (uPBTs) 

These pollutants, such as mercury and certain polycyclic aromatic hydrocarbons (PAHs), are characterized by their widespread occurrence in the environment, often resulting from historical contamination or diffuse sources that are difficult to control.

Recognising their ubiquitous nature, the Directive introduces specific provisions intended to optimise monitoring efforts. Where reliable statistical evidence demonstrates stable and representative occurrence, Member States may reduce monitoring frequency, with sampling potentially performed every three years.

To ensure that these widespread contaminants do not mask progress achieved for other pollutants, Member States may also present supplementary maps showing the chemical status of water bodies both including and excluding uPBT substances.

Although the focus is primarily on monitoring and assessment rather than additional restriction measures, industrial operators are still expected to minimise releases where technically and economically feasible and to demonstrate compliance with applicable emission limits and permit requirements.

F. Substances that accumulate in sediments or biota 

Due to their physicochemical properties, these substances tend to accumulate preferentially in living organisms and/or sediments rather than remaining dissolved in the water column. Environmental assessment must therefore extend beyond water monitoring.

The Directive requires Member States to apply Environmental Quality Standards (EQSs) established for biota and/or sediment matrices and to perform long-term trend monitoring to assess changes in concentration levels over time. Monitoring must generally be carried out at least annually unless an alternative scientifically justified approach is adopted.

For industrial operators, this means that compliance cannot be assessed solely through concentration measured in water. Releases may contribute to the accumulation of substances in sediments or aquatic organisms even when water concentrations remain relatively low. Industries may therefore be required to implement additional emission reduction measures, provide supporting environmental monitoring data, and demonstrate that their activities do not contribute to increasing trends in sediment or biota concentrations.

This category is particularly relevant for substances with bioaccumulative properties, as long-term environmental effects may occur despite relatively low concentrations in the water column.

2. Updating pollutant lists and introducing new standards

The Directive updates the lists of regulated substances in order to include several emerging pollutants or pollutants that were insufficiently covered by the existing framework.

A. PFAS: Per- and Polyfluoroalkyl Substances 

A group-based approach is prioritised.

For surface waters, an EQS is established for the sum of 25 PFAS, expressed as perfluorooctanoic acid (PFOA) equivalents.

For groundwater, a standard is established for the sum of the 20 PFAS covered by the Drinking Water Directive, together with a strict limit of 0.0044 µg/L for the sum of the four PFAS considered to be of greatest concern: PFHxS, PFOS, PFOA, and PFNA.

The Directive also pays particular attention to trifluoroacetic acid (TFA), due to its persistence, environmental prevalence, and multiple sources, including PFAS pesticides and fluorinated gases.

For surface waters, TFA is currently included in the group of “25 PFAS” subject to an overall environmental quality standard, with a relative potency factor (RPF) of 0.002 compared with PFOA.

For groundwater, although no strict individual limit has yet been established, the Commission is required to examine the establishment of a specific standard for TFA during the next legislative review.

In the longer term, the Directive stipulates that the Commission should consider the establishment of a quality standard for TFA in surface waters in order to better reflect its specific risk independently of the broader PFAS group. For groundwater, the Commission should also consider establishing a quality standard for TFA, whether separate or as a part of a sum.

B. Pesticides (PP + Biocides)

Directive (EU) 2026/805 strengthens the protection of European water resources by establishing harmonized environmental quality standards (EQSs) for pesticides, including both plant protection products and biocidal products. It introduces stricter monitoring requirements for active substances, as well as their metabolites and degradation products, in groundwater and surface waters.

For groundwater, the Directive maintains a limit of 0.1 μg/L for individual pesticides and 0.5 μg/L for the total concentration of pesticides. It also sets specific thresholds for non-relevant metabolites, with default values of 1 μg/L per substance and 5 μg/L for the total concentration.

For surface waters, a new annual average EQS of 0.2 μg/L is established for the sum of priority pesticide substances, reflecting growing concern over the effects of chemical mixtures. Plant protection products and biocides may also be regulated as River Basin Specific Pollutants (RBSPs) through national or harmonized standards.

The Directive further promotes the development of a mixture-based approach by requiring the Commission to assess the possibility of setting standards for groups of pesticides sharing the same mode of action. 

By May 2028, a harmonized EU list of relevant and non-relevant pesticide metabolites in groundwater will also be established, improving consistency in monitoring and risk assessment across Member States. Overall, the Directive strengthens pesticide management while placing continued emphasis on pollution prevention at source.

C. Pharmaceuticals

Several pharmaceutical substances are included in the regulatory annexes with specific quality standards.

These notably include carbamazepine and diclofenac for surface waters, and carbamazepine, sulfamethoxazole, and primidone for groundwater.

In order to address the cumulative risk from pharmaceuticals, the Commission should consider the setting of quality standards for the sum(s) of selected pharmaceuticals, potentially based on mode of action, at the next review.

D. Bisphenol A (BPA) & Bisphenols

Bisphenol A is now classified as a priority hazardous substance in surface waters. The Commission should review the listing of bisphenols in general at the next review and consider the establishment of an EQS for the totality of bisphenols (‘Bisphenols Total’) or at least for the sum of selected bisphenols (‘Sum of Bisphenols’), including at least Bisphenol-B and Bisphenol-S, supported by appropriate monitoring methods. 

E. Ubiquitous Persistent, Bioaccumulative and Toxic Substances — uPBTs

Substances such as mercury and polycyclic aromatic hydrocarbons (PAHs) remain subject to strict monitoring. However, Member States may reduce monitoring intensity where a reliable statistical baseline demonstrates that concentrations remain stable.

Beyond the substance-by-substance updates, the Directive strengthens the consideration of cumulative effects associated with pollutant mixtures.

3. EFB methods

For surface waters, an EQS is introduced for the sum of pesticides already listed as priority substances in order to better address cumulative risks. The Commission is also invited to consider, during future reviews, the establishment of standards for groups of substances sharing a common mode of action.

This development is accompanied by the introduction of effect-based monitoring methods, allowing cumulative biological effects to be assessed beyond a strictly analytical approach. Such methods should notably be applied to oestrogenic substances as a complement to conventional monitoring methods.

4. Vigilance mechanisms: watch lists

Watch lists are an anticipatory tool intended to collect data on emerging pollutants for which the available knowledge remains insufficient.

They help guide future reviews of regulated substance lists and prepare for the possible establishment of new environmental quality standards.

For surface waters, the watch list may include up to ten substances or groups of substances. A similar mechanism is introduced for groundwater, although the groundwater watch list is limited to five substances.

The inclusion of microplastics and antimicrobial resistance (AMR) indicators will become mandatory on both watch lists as soon as reliable and affordable monitoring methods are available.

Member States must monitor each substance included on a watch list for a period of 24 months.

The number of monitoring stations is strictly defined:

• For surface waters, the monitoring system is based on population and geographical area. It must include at least one monitoring station, with one additional station per million inhabitants and further stations depending on the surface area concerned.

• For groundwater, at least two monitoring stations are required, together with one additional station for every 45,000 km² of groundwater bodies.

5. The role of ECHA

A major institutional change is the transfer of scientific expertise to the European Chemicals Agency (ECHA).

ECHA is now responsible for preparing the scientific reports required for the three-year review of watch lists and the six-year review of priority pollutant lists.

ECHA therefore becomes a central and permanent source of scientific support for the Commission in identifying candidate substances, preparing scientific reports, and proposing environmental quality standards or threshold values.

This centralisation is intended to ensure consistency between water legislation and other regulatory frameworks, including REACH, pesticide legislation, and veterinary medicinal product legislation.

ECHA must also integrate data generated by innovative technologies, such as remote sensing and the Copernicus programme, into its assessments.

6. Modernisation of reporting and digitalisation

The Directive requires faster data transmission in order to enable more dynamic monitoring of water status.

Member States must ensure the electronic transmission of data through the EEA’s Reportnet system, allowing automated reporting.

The reporting frequency is increased: validated chemical data must be reported every two years, while biological data must be reported every three years.

The framework also explicitly encourages the use of technological innovations, including artificial intelligence, Earth observation, and citizen science, to complement traditional monitoring networks.

7. Liability and access to Justice

The Directive strengthens citizens’ rights and the responsibilities of economic operators.

Member States must guarantee access to justice in accordance with the Aarhus Convention, allowing members of the public concerned and environmental non-governmental organisations to challenge the legality of decisions or omissions associated with the implementation of the Directive.

In addition, the Commission must publish, by 2029, a report assessing the feasibility of introducing an extended producer responsibility scheme. Such a mechanism could require producers to contribute to the costs of monitoring programmes for substances they place on the market.

8. Specific provisions and exceptions

The Directive establishes strict frameworks for certain projects and activities.

1. In the short term, a project is not considered to constitute an infringement where its adverse impacts are no longer detectable after one year, or after three years for biological parameters, and provided that strict mitigation conditions are fulfilled.

2. The transfer of water and sediments is permitted provided that it does not result in a net increase in the pollutant load, that all mitigation measures are implemented, and that drinking-water abstraction areas are protected by appropriate exclusion zones.

9. Implementation deadlines and compliance roadmap

The Directive provides for progressive implementation, with several key deadlines.

These deadlines require the early identification of relevant substances, appropriate monitoring methods, and the actions needed to ensure compliance.

Conclusion

Directive (EU) 2026/805 represents a major development towards more integrated water management based on scientific rigor and digital transparency.

In particular, it strengthens the assessment of chemical status by integrating pollutants specific to individual river basins and by expanding automated monitoring and reporting systems.

For both public authorities and operators, the main challenges will involve integrating these new parameters into their compliance strategies and managing increasingly complex monitoring protocols, particularly for emerging substances such as PFAS, pharmaceutical residues, and microplastics.

The centralization of data at European level and the strengthened role of specialized agencies will also increase the level of regulatory scrutiny and the frequency of controls.

In this context, a proactive approach is becoming essential. The Directive confirms that the management of water quality can no longer rely solely on downstream monitoring. It must instead be supported by a better understanding of the substances placed on the market, their uses, their emissions, and their environmental fate.

Our expertise should enable industrial operators to anticipate changes in environmental quality standards and the inclusion of new substances, thereby securing their regulatory compliance and placing their activities on a sustainable pathway.

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Authors: Flolriane DEMAILLY & Loris MISTRULLI