Edastuskiri

Commission européenne/Europese Commissie, 1049 Bruxelles/Brussel, BELGIQUE/BELGIË - Tel. +32 22991111

[email protected]

EUROPEAN COMMISSION DIRECTORATE-GENERAL

ENVIRONMENT Directorate C –Zero Pollution, Water Resilience & Green Urban Transition

ENV.C.2 –Marine Environment & Clean Water Services

Brussels ENV.C.2/BL

To the Members of the recast Drinking Water Directive Expert Group

Sent by email only

Subject: Support to Member States for their communication to the Commission

under Article 4(3) of the recast Drinking Water Directive – use of the

water leakage level template

Dear member of the Drinking Water Expert Group,

In line with Article 4(3) of the recast Drinking Water Directive 2020/2184, (hereafter

‘the Directive’) Member States shall ensure that an assessment of water leakage levels

within their territory and of the potential for improvements in water leakage reduction is

carried out using the infrastructural leakage index (ILI) rating method or another

appropriate method. That assessment shall take into account relevant public health,

environmental, technical and economic aspects and cover at least water suppliers

supplying at least 10 000 m³ per day or serving at least 50 000 people. The results of this

assessment shall be communicated to the Commission by 12 January 2026.

At the request of the members of the Drinking Water Expert Group, a “water leakage

level” subgroup was established end of 2024 to further develop members’ preferred

water leakage indicator. This subgroup developed a water leakage level (WLL) template

which was presented at the expert group on 12 June 2025. Following this meeting, a

majority of Member States informed the Commission services that they would use this

template for their communication to the Commission under Article 4(3) of the Directive.

To support Member States in their communication to the Commission and to harmonise

the assessment results, I would recommend that Member States’ competent authorities

use this template. In annex you can find the template presented at the expert group

meeting of 12 June 2025, which is also available on the Commission’s DWEG

CIRCABC platform.

I am aware that some Member States expressed some doubts on the interpretation of

some data requested in this template. To prevent misinterpretation of data provided, if

necessary, my colleagues can organise subsequent bilateral meetings with expert group

members.

By 2028, the Commission will adopt a delegated act setting out a threshold above which

Member States shall present an action plan. This delegated act will be defined using the

2

Member States’ assessments and the Union average leakage rate determined on the basis

of those assessments. The Commission will consult the expert group before adopting the

delegated act.

In line with Article 4(3) of the Directive, within two years of the adoption of this

delegated act, Member States having a leakage rate exceeding the threshold set out in the

delegated act must present an action plan to the Commission laying down a set of

measures to be taken in order to reduce their leakage rate.

Should you would have any questions about the use or interpretation of the data

requested in the template, please contact us via the functional mailbox ENV-

[email protected].

Thank you for your cooperation.

Yours sincerely,

(e-signed)

Paula DUARTE GASPAR

Head of Unit

Annex: Water leakage level template (.xls format)

c.c.: [email protected]; [email protected]

Electronically signed on 29/10/2025 10:51 (UTC+01) in accordance with Article 11 of Commission Decision (EU) 2021/2121

Commission européenne/Europese Commissie, 1049 Bruxelles/Brussel, BELGIQUE/BELGIË - Tel. +32 22991111

[email protected]

EUROPEAN COMMISSION DIRECTORATE-GENERAL

ENVIRONMENT Directorate C –Zero Pollution, Water Resilience & Green Urban Transition

ENV.C.2 –Marine Environment & Clean Water Services

Brussels ENV.C.2/BL

To the Members of the recast Drinking Water Directive Expert Group

Sent by email only

Subject: Support to Member States for their communication to the Commission

under Article 4(3) of the recast Drinking Water Directive – use of the

water leakage level template

Dear member of the Drinking Water Expert Group,

In line with Article 4(3) of the recast Drinking Water Directive 2020/2184, (hereafter

‘the Directive’) Member States shall ensure that an assessment of water leakage levels

within their territory and of the potential for improvements in water leakage reduction is

carried out using the infrastructural leakage index (ILI) rating method or another

appropriate method. That assessment shall take into account relevant public health,

environmental, technical and economic aspects and cover at least water suppliers

supplying at least 10 000 m³ per day or serving at least 50 000 people. The results of this

assessment shall be communicated to the Commission by 12 January 2026.

At the request of the members of the Drinking Water Expert Group, a “water leakage

level” subgroup was established end of 2024 to further develop members’ preferred

water leakage indicator. This subgroup developed a water leakage level (WLL) template

which was presented at the expert group on 12 June 2025. Following this meeting, a

majority of Member States informed the Commission services that they would use this

template for their communication to the Commission under Article 4(3) of the Directive.

To support Member States in their communication to the Commission and to harmonise

the assessment results, I would recommend that Member States’ competent authorities

use this template. In annex you can find the template presented at the expert group

meeting of 12 June 2025, which is also available on the Commission’s DWEG

CIRCABC platform.

I am aware that some Member States expressed some doubts on the interpretation of

some data requested in this template. To prevent misinterpretation of data provided, if

necessary, my colleagues can organise subsequent bilateral meetings with expert group

members.

By 2028, the Commission will adopt a delegated act setting out a threshold above which

Member States shall present an action plan. This delegated act will be defined using the

2

Member States’ assessments and the Union average leakage rate determined on the basis

of those assessments. The Commission will consult the expert group before adopting the

delegated act.

In line with Article 4(3) of the Directive, within two years of the adoption of this

delegated act, Member States having a leakage rate exceeding the threshold set out in the

delegated act must present an action plan to the Commission laying down a set of

measures to be taken in order to reduce their leakage rate.

Should you would have any questions about the use or interpretation of the data

requested in the template, please contact us via the functional mailbox ENV-

[email protected].

Thank you for your cooperation.

Yours sincerely,

(e-signed)

Paula DUARTE GASPAR

Head of Unit

Annex: Water leakage level template (.xls format)

c.c.: [email protected]; [email protected]

Electronically signed on 29/10/2025 10:51 (UTC+01) in accordance with Article 11 of Commission Decision (EU) 2021/2121