United Utilities Group PLC

Prospectus • Jul 24, 2025

SUPPLEMENTARY OFFERING CIRCULAR DATED 22 JULY 2025

UNITED UTILITIES PLC (incorporated with limited liability in England)

UNITED UTILITIES WATER FINANCE PLC (incorporated with limited liability in England)

with obligations under Notes issued by United Utilities Water Finance PLC to be unconditionally and irrevocably guaranteed by

UNITED UTILITIES WATER LIMITED (incorporated with limited liability in England)

GBP 10,000,000,000 Euro Medium Term Note Programme

This Supplementary Offering Circular (the "Supplement") to the Offering Circular dated 18 November 2024 (the "Offering Circular", which definition includes the Offering Circular as supplemented on 30 January 2025, 13 February 2025 and 15 May 2025 and as supplemented, amended or updated from time to time and includes all information incorporated by reference therein) which constitutes a base prospectus for the purposes of Regulation (EU) 2017/1129 as it forms part of domestic law in the United Kingdom by virtue of the European Union (Withdrawal) Act 2018, as amended (the "UK Prospectus Regulation"), constitutes a supplementary prospectus for the purposes of section 87G of the Financial Services and Markets Act 2000 and is prepared in connection with the GBP 10,000,000,000 Euro Medium Term Note Programme (the "Programme") established by United Utilities PLC ("UU") and United Utilities Water Finance PLC ("UUWF") (each an "Issuer" and together the "Issuers"). The payment of all amounts due in respect of Notes issued by UUWF will be unconditionally and irrevocably guaranteed by United Utilities Water Limited ("UUW" or the "Guarantor").

This Supplement is supplemental to, forms part of, and should be read in conjunction with, the Offering Circular and any other supplements to the Offering Circular issued by the Issuers. Except as otherwise provided in this Supplement, terms and expressions defined in the Offering Circular shall have the same meaning when used herein.

Each of the Issuers and the Guarantor (together, the "Responsible Persons") accepts responsibility for the information contained in this Supplement. To the best of the knowledge of each of the Responsible Persons the information contained in this Supplement is in accordance with the facts and this Supplement does not omit anything likely to affect the import of such information.

Neither this Supplement nor any other information supplied in connection with the Programme or the issue of any Notes constitutes an offer or invitation by or on behalf of the Issuers, the Guarantor, any of the Dealers or the Trustee to any person to subscribe for or to purchase any Notes.

This Supplement has been approved by the FCA, as competent authority for the purposes of the UK Prospectus Regulation, as a supplement to the Offering Circular.

1. Purpose

The purpose of this Supplement is to:

• (A) incorporate by reference the Annual Report and Financial Statements for the year ended 31 March 2025 for UU ("UU's Report and Financial Statements");
• (B) incorporate by reference the Report and Financial Statements for the year ended 31 March 2025 for UUWF ("UUWF's Report and Financial Statements");
• (C) incorporate by reference the Annual Report and Financial Statements for the year ended 31 March 2025 for UUW ("UUW's Report and Financial Statements");
• (D) incorporate by reference the Annual Report and Financial Statements for the year ended 31 March 2025 for United Utilities Group PLC ("UUG") ("UUG's Report and Financial Statements");
• (E) update the sections entitled "Risk Factors Regulatory environment & framework" and "Description of the Guarantor – United Utilities Water Limited – Environmental regulation" on pages 16 and 120 (respectively) of the Offering Circular;
• (F) update the "no significant change" statement in the Offering Circular; and
• (G) update the "no material adverse change" statement in the Offering Circular.

2. Documents incorporated by reference

• 2.1 The following documents were published on the dates appearing below:
  • (A) UU's Report and Financial Statements, 15 July 2025 (accessible at https://www.unitedutilities.com/globalassets/documents/corporate-documents/unitedutilites-plc-mar-25-v1.0-final---signed.pdf);
  • (B) UUWF's Report and Financial Statements, 15 July 2025 (accessible at https://www.unitedutilities.com/globalassets/documents/corporate-documents/uuwater-finance-plc-stats---mar-25-vfinal---signed.pdf);
  • (C) UUW's Report and Financial Statements, 15 July 2025 (accessible at https://www.unitedutilities.com/globalassets/documents/corporate-documents/uuwannual-report-and-financial-statements-2025---final-signed.pdf); and
  • (D) UUG's Report and Financial Statements, 23 June 2025 (accessible at https://www.unitedutilities.com/globalassets/documents/pdf/integrated-annual-report-2025).
• 2.2 By virtue of this Supplement:
• (A) UU's Report and Financial Statements is hereby incorporated in, and forms part of, this Supplement, and is thereby incorporated in, and forms part of, the Offering Circular;
• (B) UUWF's Report and Financial Statements is hereby incorporated in, and forms part of, this Supplement, and is thereby incorporated in, and forms part of, the Offering Circular;
• (C) UUW's Report and Financial Statements is hereby incorporated in, and forms part of, this Supplement, and is thereby incorporated in, and forms part of, the Offering Circular; and
• (D) UUG's Report and Financial Statements is hereby incorporated in, and forms part of, this Supplement, and is thereby incorporated in, and forms part of, the Offering Circular.

3. Update to the sections entitled "Risk Factors – Regulatory environment & framework" and "Description of the Guarantor – United Utilities Water Limited – Environmental regulation" on pages 16 and 120 (respectively) of the Offering Circular

The following paragraph shall be added to the end of: (i) the "Regulatory environment & framework" sub-section of the "Risk Factors" section of the Offering Circular; and also (ii) the "Economic regulation" sub-section of the "Description of the Guarantor – United Utilities Water Limited" section of the Offering Circular:

"In October 2024, the UK Government launched an independent commission into the water industry (the "Cunliffe Review"), with the aim of modernising and streamlining existing regulation and the intention of forming the basis of further legislation for the attraction of long-term investment in the sector. In February 2025, the independent commission published a public call for evidence in relation to the Cunliffe Review, and interim conclusions were published in June 2025. On 21 July 2025, the final report (the "Cunliffe Report") was submitted to the UK and Welsh Governments, outlining the full recommendations in relation to (amongst other things) strategic direction and planning, legislative framework, regulatory reform, company structures, ownership, governance and management, and infrastructure and asset health, including proposals to abolish Ofwat. The Group is currently reviewing the Cunliffe Report findings. If implemented, the Cunliffe Report recommendations could radically change the legislative and regulatory framework within which the Group currently operates and therefore require the diversion of resources towards adapting to a new set of sector-wide rules."

4. No significant change statement

There has been no significant change in the financial position or financial performance of each of UU, UUWF and UUW since the date of their respective last published audited annual financial statements, being 31 March 2025.

5. No material adverse change statement

There has been no material adverse change in the prospects of each of UU, UUWF and UUW since the date of their respective last published audited annual financial statements, being 31 March 2025.

6. General

Save as disclosed in this Supplement there has been no other significant new factor, material mistake or inaccuracy relating to information included in the Offering Circular since the publication of the Offering Circular.

Copies of this Supplement and all information incorporated by reference in this Supplement and the Offering Circular can be obtained from the Issuers in the manner described in the Offering Circular.

To the extent that there is any inconsistency between (a) any statement in this Supplement and (b) any other statement in, or incorporated by reference in, the Offering Circular, the statements in this Supplement will prevail.

If documents which are incorporated by reference themselves incorporate any information or other documents therein, either expressly or implicitly, such information or other documents will not form part of this Supplement for the purposes of the UK Prospectus Regulation except where such information or other documents are specifically incorporated by reference to this Supplement or where this Supplement is specifically defined as including such information. Any information contained in a document incorporated by reference in this Supplement which is not incorporated in, and does not form part of, this Supplement is not relevant for investors or is contained elsewhere in this Supplement.

No person is or has been authorised by the Issuers to give any information or to make any representation not contained in or not consistent with the Offering Circular or this Supplement or any other information supplied in connection with the Programme or the Notes and, if given or made, such information or representation must not be relied upon as having been authorised by the Issuers, any of the Dealers or the Trustee.

Neither the delivery of the Offering Circular and/or this Supplement nor the offering, sale or delivery of any Notes shall in any circumstances imply that the information contained herein concerning the Issuers is correct at any time subsequent to the date hereof or that any other information supplied in connection with the Programme is correct as of any time subsequent to the date indicated in the document containing the same. Copies of UU's Report and Financial Statements, UUWF's Report and Financial Statements, UUW's Report and Financial Statements and UUG's Report and Financial Statements, each of which is incorporated by reference into, and forms part of, this supplement, are available for viewing at https://data.fca.org.uk/#/nsm/nationalstoragemechanism.