United Utilities Water Limited: Treatment Works and Connected Supply Systems Risk Assessment Compliance

Notice under regulation 27(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)

Reference: UUT-2026-00002

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): United Utilities Water Limited, with registered number 02366678 (hereinafter called ‘the company’).

Assets affected:

Whole company.

Details of this Notice:

1. This Notice is served on the company by the Drinking Water Inspectorate on behalf of the Secretary of State, under regulation 27(4) of the Water Supply (Water Quality) Regulations 2016 (as amended) for the assets listed above, for risks associated with Drinking Water Safety Planning (DWSP).

Requirements:

2. The company are required to satisfy the following:

(a) Review of a risk assessment:

1. Submit a revised DWSP methodology implementing the following factors:

• Define which stages of the supply system, risk assessments (for assets such as raw water mains and pumping stations) are to be assessed in. Derive an approach that ensures all linked assets are evaluated consistently using the updated methodology.
  Date by which requirement must be satisfied: 31 July 2026
• Review the company’s risk-scoring methodology to ensure a clear and traceable link between hazard identification, including by operational teams, and risk assessment enabling the effective identification of significant risks. Verify that hazards and hazardous events are consistently and appropriately scored, and that the categorisation accurately reflects the stage of the planned mitigation to address the drinking water quality risks identified. The methodology should also clearly set out how significant risks are prioritised for management and mitigation.
  Date by which requirement must be satisfied: 30 September 2026
• Improve existing internal processes to evaluate if existing control measures are practical and effective so that the true residual risks to consumers are understood. Review the maintenance, procedural, and inspection‑based controls to confirm they are appropriate and sufficient to reduce risks to the levels reported in regulation 28 submissions.
  Date by which requirement must be satisfied: By the dates listed in Annex 1.

2. Provide a programme of risk assessments to assess all risks at all raw water assets and treatment sites listed in Annex 1.

• Use the updated risk‑assessment methodology including strengthened risk identification, improved scoring, and updated control‑measure evaluation to complete full risk assessments of all water treatment works and their supplying raw‑water assets. These assessments must include identification of single points of failure and an evaluation of the treatment process robustness, resilience, and effectiveness under potential variations in raw‑water quality and quantity.
  Date by which requirement must be satisfied: By the dates listed in Annex 1.

3. Submit revised risk scoring and control measure data for regulation 28 reports.
Date by which requirement must be satisfied: By the dates listed within annex 1.

(b) Reporting:

1. Submit a revised DWSP methodology.
Date by which requirement must be satisfied: 31 October 2026

2. Submit a revised DWSP Risk Assessment for Watchgate WTW.
Date by which requirement must be satisfied: 31 March 2027

3. Submit the revised and/or new risk assessments, accompanied by a Board level Director sign-off.
Date by which requirement must be satisfied: As soon as reasonably practicable upon completion. It is anticipated this would be by 3 months after the completion of the risk assessments

Signed

Nicholas Adjei

Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs

25 June 2026

Reference: UUT-2026-00002 v1

Annex 1

A prioritised list of all raw water and treatment assets, beginning with the higher priority sites (as determined by the company) to be reassessed for risks as described within the notice.