Castle Water Wholesale Limited – Design, construction and commissioning of new water treatment works on the former Didcot Power Station site supplying Thames Water Utilities Limited’s water supply zone(s)

Water Industry Act 1991 (as amended) (“the Act”): Section 19(1)(b)

Reference: CWL-2023-00001

Acceptance Notice:

The Drinking Water Inspectorate, on behalf of the Secretary of State for Environment, Food and Rural Affairs:

1. Is satisfied that Castle Water Wholesale Limited “the company” in supplying water from the treatment works on the former Didcot Power Station site which may be at risk of exceeding the standards for all Parameters. This means that the company is likely to contravene its duty in respect of supplying water which meets the Regulations under Section 68(1)(a) of the Water Industry Act 1991 and meets the requirement set in regulation 4(2)(c) of the Water Supply (Water Quality) Regulations 2016 (as amended) (“the Regulations”).
2. Has notified the company on 19 December 2023 that the Secretary of State is considering making in relation to the company an enforcement order under Section 18 of the Act.
3. Notes that the company has on 3 September 2024 given a new undertaking under Section 19 (1) (b) of the Act, to take the following steps by the dates shown.

Steps to be taken

1. The company will ensure that water supplied from the proposed treatment works reaches the wholesomeness standard under regulation 4 (under the regulations) before introduction into the service of the Recipient’s supply networks.
   Steps to be taken prior to delivery date are:

• Works fully constructed and commissioned and running to waste/recirculation (as appropriate).
• All pre introduction testing completed (including satisfactory Reg 15 sampling), documented and signed off.
• Drinking water safety planning carried out, signed off and reported.

Date: TBC

2. Develop the outline building designs for the proposed abstraction point, water treatment works, raw and treated pipework, run to waste facilities and supply point.
   Date: Completed
3. Develop and implement a company Drinking Water Safety Plan to address the risk of parameter failures associated with the connected supply system supplied by the proposed WTW including the risk assessment methodology.
   Once a decision is made to move from outline to detailed design of the water treatment works, the following steps will be taken

• A yearlong (minimum) monitoring programme of raw water at the River Thames abstraction point.
• Consultation with catchment stakeholders will also commence.
• Methodology will be developed in parallel, and completed (first issue) before construction is completed.

Date: TBC

4. Develop and implement the policy for the management of sampling and analysis (including out of hours emergency sampling) and how the assessment of analytical results will be conducted and by whom.

• Sampling and analysis, as per category (a) source requirements, will be carried out by the chosen plant operating service provider, within their operational contract; analysis will be carried out at their designated analysis facilities.
• All sampling related matters to be specified, approved and audited by the company.
• All water quality data analysis, investigations and breach reporting will be analysed by the company’s water quality manager/team.
• All requirements formalised and in place prior to pre-introduction testing commencement.

Date: TBC

5. Develop and implement the detail on how the company will conduct its risk assessments under regulation 15 (under the regulations) (which will need to be submitted to DWI before the source enters supply).
   To be developed as part of detailed design. Risk assessments submitted at least one month before pre-introduction testing commencement.
   Date: TBC

6. Develop and implement the company’s policies and procedures associated with regulatory compliance monitoring, for investigations of PCV breaches and the triggers utilised for drinking water quality event investigations.
   To be developed during design, construction and commissioning, with a view to be being sufficiently matured and signed off prior to pre-introduction testing commencement.
   Date: TBC

7. Develop and implement the company’s disinfection policy and any procedures or documents associated to this, which show the monitoring in place, any alarm and shutdown controls and response instructions to staff.
   To be drafted and developed early on in detailed design as will impact civil, electrical, mechanical and instrument/control/automation design of the plant. First issue ready prior to pre-introduction testing commencement.
   Date: TBC

8. Develop and implement the company’s policies and procedures associated with out of hours response to drinking water quality events.
   To be signed off (first issue) prior to pre-introduction testing commencement.
   Date: TBC

9. Develop and implement the details of the data reporting mechanisms that will be employed by the company in compliance of The Water Industry (Suppliers’ Information) Direction 2021.
   All data reporting tables to be built and tested with dummy data, and the Inspectorate satisfied with data transfer, prior to pre-introduction testing commencement.
   Date: TBC

10. Develop and implement the Company’s policies and procedures associated with ensuring compliance with regulation 31 for products and substances in contact with drinking water.
    First issue signed off and issued prior to pre-introduction testing commencement.
    Date: TBC

11. Develop and implement a programme for the ongoing review of all policies and procedures relating to the production of wholesome water for regulation 4(1) (under the regulations) purposes that includes: – how the ongoing programme will be documented to evidence when reviews are completed, and any changes made; and – how updates to procedures or policies will be communicated to relevant personnel.
    All policy and procedural documentation will be part of the Quality Management System (e.g. ISO 9000) and will be reviewed as required – either following substantive change or relevant event/occurrence or a minimum period. Process signed off and issued prior to pre-introduction testing and on testing commencement.
    Date: TBC

12. Develop and implement the policies and procedures for monitoring the technical competence of those operating the abstraction point and water treatment works including implementation of training record documentation: – Implementation of an ongoing process to review training programmes to ensure training packages remain accurate and up to date; and – Implementation of an on-going quality-controlled system to ensure relevant personnel are re-trained following the revisions of policies, procedures or systems.
    It is expected that the plant operating service provider will have an established and relevant competency and training framework in place, such as licence to operate, for anyone who operates, maintains and supervises the treatment works, including non-regular and out of hours support staff.
    An induction will be developed and reviewed for visitors and contractors.
    The framework will be reviewed and developed on an on-going basis, to ensure it is up to date and all those involved with the operation of the plant are fully trained and the training is up to date, including any formal/mandatory requirements.
    The system will be fully reviewed by the company and amended as required to suit the requirements of the treatment works and associated plant. The company will also audit on a regular and ongoing basis. All policies and standards (first issue), and all personal sign-off prior to pre-introduction testing.
    Date: TBC

13. Develop and implement the policies and procedures associated with operational communications with the abstraction point owner.
    Consultation to be held with abstraction point owner during construction and commissioning.
    First issue of communications policies/plans ready for pre-introduction testing commencement. Provision made for 24 hour contact.
    Date: TBC

14. Develop and implement the policies and procedures associated with operational communications with the Recipient including details of how the company will work with the Recipient to assist with investigations into compliance failures, water quality events and water quality complaints.
    Consultation to be held with the incumbent water company during construction and commissioning.
    First issue of communications policies/plans ready for pre-introduction testing commencement. Provision made for 24 hour contact.
    Date: TBC
15. Develop and implement the contaminated land assessments and report any remediation required. Detail how the company have risk assessed assets being placed under ground, and if barrier pipe is required and how contact and treated water storage tanks will be protected if buried.
    Date: TBC

16. Develop and implement the policies and procedures associated with complying with the Security and Emergency Measures (Water and Sewerage Undertakers and Water Supply Licensees) Direction 2022.
    To be developed and reviewed first during the design phase to ensure all requirements are captured, and then matured into the construction project phase. First issue for pre-introduction testing.
    Date: TBC

17. Develop the policies and procedures associated with complying with the Network and Information Systems Regulations 2018.
    To be developed and reviewed first during the design phase to ensure all requirements are captured, and then matured into the construction project phase. First issue for pre-introduction testing.
    Date: TBC

18. Develop a risk assessment under regulation 27 (under the regulations) before supply is made from the abstraction source.
    To be delivered in line with step (c).
    Date: TBC

Reporting

1. Provide an annual report stating the progress of the project.
   Date: By 31 January 2025 and then annually on that date for the duration of the Undertaking
2. Provide evidence of the completion of each individual step stated in Section 4. Date: 1 month after the individual Section 4 completion dates
3. Provide confirmation of the completion of construction of the abstraction point, water treatment works, raw and treated water pipework and the supply point.
   Formal notification to be given once the company has signed off construction. Construction may continue through commissioning, but only those works that do not affect the operation of the treatment process.
   Date: TBC
4. Submit a project completion report for the Inspectorate to review and sign off before agreement is given for ANY water to be put into supply. The report will include documentation to confirm that Steps to be Taken actions as set out in this Undertaking have been taken.
   Date: TBC
5. Submit a final report on the conclusions drawn from the work carried out as part of this Undertaking.
   Date: 1 year and 1 month after date of 5(d)

Further Details of this Acceptance Notice:

1. The Secretary of State is satisfied that Castle Water Wholesale Limited has given and is complying with an undertaking to take all such steps as appear to the Secretary of State for the time being to be appropriate to secure or facilitate compliance with the requirement of regulation 4(2)(c) of the Water Supply (Water Quality) Regulations 2016 (as amended).

Authorised by the Secretary of State to sign in that behalf

Nicholas Adjei
Deputy Chief Inspector, Drinking Water Inspectorate
24 October 2024
Reference: CWL-2023-00001