Thames Water Utilities Limited: Air Valve Risk Assessment

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

Reference: TMS-2024-00014

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Thames Water Utilities Limited, with registered number 02366661 (hereinafter called ‘the Company’).

Assets affected:

• All treatment works, service reservoirs and water supply zones within the company’s operating area.
  

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 contamination via ingress into air valves.
   

Requirements:

2. The Company are required to satisfy the following:
   

(a) Carry out a risk assessment:

1. Design and implement an asset register for all air valve assets.
   Date by which requirement must be satisfied: 30 October 2025
   
2. Implement a process for risk assessing air valve assets.
   Date by which requirement must be satisfied: 28 February 2025
   
3. Implement the risk-based maintenance activity on all air valves, which shall include:
   
   – 3 monthly inspections for high-risk valves.
   – 12 monthly inspections for medium-risk valves.
   – Remedial works to air valves where inspections have highlighted an issue.
   Date by which requirement must be satisfied: 28 February 2025
   
4. Use the information gathered from steps (a) 2-3 to inform the company’s Drinking Water Safety Plans and carry out a regulation 27 risk assessment for contamination via ingress into air valves in all water supply zones operated by the company.
   Date by which requirement must be satisfied: 30 April 2025
   

(b) Review of a risk assessment:

1. Not applicable.
   

(c) Reporting:

1. Submit the new risk assessments as outlined in step (a)4, 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 commence by 30 June 2025.
   

Signed

Nicholas Adjei

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

6 December 2024

Reference: TMS-2024-00014 v1