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Thames Water Utilities Limited – Sheeplands works Cryptosporidium

Notice under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)

Reference: TMS-2024-00002

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:

  • T06U.643 Sheeplands works (Bowsey)
  • T06U.638 Sheeplands works 2 District
  • YTMS1200 Henley Supply System
  • T06U.627 Harpsden works

Details of this Notice:

  1. The Drinking Water Inspectorate (‘the Inspectorate’) has received a regulation 28(1) report of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated 20 March 2024, which states that there is or has been a significant risk of supplying water from Sheeplands works (and associated assets as applicable) that could constitute a potential danger to human health or could be unwholesome.
  2. Consequently, this Notice is served on the Company by the Inspectorate on behalf of the Secretary of State, under regulation 28(4) for the assets listed above, for risks associated with:

Description of Risk

Hazard/ Hazardous Event/ Parameter

Hazard I D

Failure of treatment process to prevent Cryptosporidium entering supply

Cryptosporidium

TMS-4-T06U.638-MDCT007-T06U.638-C111A, TMS-4-T06U.638-MDCT007-T06U.643-C111A and TMS-4-T06U.627-MDCT007-T06U.627-C111A

Table 1: Table of the hazards, hazardous events, and/or parameters covered by this Notice, including the Hazard I D numbers and the description of risks.

  1. The Company are required to satisfy the following requirements.

The date given is that until or by which the requirements must be maintained or satisfied, as appropriate.

Requirements:

(a) To maintain the following measures for the period specified in each case:

  1. Continuous monitoring for Cryptosporidium at defined locations along the Harpsden main, Sheeplands works and at Bowsey Service Reservoir.
    Date: Ongoing for the duration of this Notice.
  2. Operation of all treatment processes at Sheeplands works, within defined operating ranges with appropriate triggers, responses, and contingency arrangements.
    Date: Ongoing for the duration of this Notice.
  3. Water Quality response procedures in place for investigation of contraventions including process optimisation and reporting, consumer complaints and event response.
    Date: Ongoing for the duration of this Notice.
  4. Maintain contingency plans for the protection of public health associated with drinking water quality, to include liaison with Local Authorities and the United Kingdom Health Security Agency (UKHSA).
    Date: Ongoing for the duration of this Notice.
  5. Ongoing surveillance of all air valves along the Harpsden raw water main.
    Date: Ongoing for the duration of this Notice.

(b) To review, revise or make operational the following measures, by the dates specified in each case:

  1. Produce an outline plan for the management and resolution of Cryptosporidium risks at the Sheeplands and Harpsden works.
    Date: 30 September 2024.
  2. Take all necessary actions to reduce risk of ingress via the Harpsden raw water main.
    Date: 31 August 2025.
  3. Conduct a trial for running the Harpsden raw water main supply through the treatment process (Pall Plant) at Sheeplands works.
    Date: 31 December 2024.
  4. Identify preferred treatment option for the long term future of the Sheeplands and Harpsden works, using the results from the trial conducted in measure b(3).
    Date: 30 June 2025.
  5. Produce delivery plan for implementation of preferred treatment option in (b)4.
    Date: 30 September 2025.
  6. Complete the installation and commissioning of preferred treatment option in (b)4.
    Date: 30 June 2026.

(c) To audit whether the measures have been effective by the following means:

  1. Define an audit strategy to monitor the effectiveness of the measures specified in sections (a) and (b).
    Date: 31 October 2024.
  2. Implement, and keep under continuous review, the audit strategy defined in measure (c)1.
    Date: Following completion of measure (c)1. onwards.

(d) Not to supply water for regulation 4(1) purposes from Sheeplands or Harpsden works, or not to so supply unless the specified conditions below are satisfied:

  1. Not Applicable.

(e) To provide the following information in the time and manner specified below to enable monitoring of progress towards the mitigation of the risks:

  1. Provide a progress report annually.
    Date: by 31 January each year.
  2. Provide the outcomes from the outline plan for the management and resolution of Cryptosporidium risks at the Sheeplands and Harpsden works, as specified in measure b(1).
    Date: 31 October 2024.
  3. Provide confirmation and evidence of actions taken to reduce ingress via the Harpsden raw water main, as required in measure b(2).
    Date: 30 September 2025.
  4. Provide the outcome of the trial that was conducted in measure b(3).
    Date: 31 January 2025.
  5. Provide a report to confirm the identification of the preferred option for Sheeplands and Harpsden works, as specified in measure b(4).
    Date: 31 July 2025.
  6. Provide the delivery plan for the implementation of the preferred option.
    Date: 31 October 2025.
  7. Provide evidence for the installation and commissioning of the preferred option in measure (b)4.
    Date: 31 July 2026.
  8. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 30 November 2024.
  9. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision.
  10. Submit a report in the event that any completed measures of this Notice need to be altered in any way, for any reason.
    Date: Ongoing for the duration of this Notice.
  11. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 August 2027.

Further Details of this Notice:

  1. Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
  2. Under regulation 28(6) the Inspectorate, on behalf of the Secretary of State, may by notice served on the Company, revoke or vary this Notice.
  3. Failure by the Company to comply with this Notice may result in enforcement proceedings under section 18 of the Water Industry Act 1991 (as amended).

Signed

 

Nicholas Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
14 August 2024
Reference: TMS-2024-00002 v1

 

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