Yorkshire Water Services Limited – Treated water and through process tank inspection notice

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

Reference: YKS-2021-00002

Version Number: 2

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Yorkshire Water Services Limited, with registered number 02366682 (hereinafter called ‘the Company’).

Assets Affected:

• All contact tanks, treated water storage tanks, and service reservoirs (hereafter collectively referred to as ‘tanks’) used to supply water for regulation 4(1) purposes within the Yorkshire Water Services Limited supply region.
• All the company’s interstage tanks, washwater tanks, and through process tanks (hereafter referred to as ‘process tanks’)

Details of this Notice:

1. The Drinking Water Inspectorate (‘the Inspectorate’) has received a set of regulation 28(1) reports of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated between 11 December 2020 and 22 September 2021, which state that there is or has been a significant risk of supplying water from the company’s through process (interstage) tanks, contact tanks, clean water tanks, and service reservoirs (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 the integrity of treated water storage (inc. ingress).	Total Coliforms (Confirmed)	Multiple hazard IDs, for example: 27181
Failure of the integrity of treated water storage (inc. ingress).	Enterococci (Confirmed)	Multiple hazard IDs, for example: 27180
Failure of the integrity of treated water storage (inc. ingress).	Cryptosporidium	Multiple hazard IDs, for example: 27179
Failure of the integrity of treated water storage (inc. ingress).	Clostridium perfringens (Confirmed)	Multiple hazard IDs, for example: 27178
Failure of the integrity of treated water storage (inc. ingress).	E. coli (Confirmed)	Multiple hazard IDs, for example: 11760
Water Quality Issues due to inadequate maintenance and inspection.	E. coli (Confirmed)	Multiple hazard IDs, for example: 14174

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.

3. 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. Operate all tanks and process tanks in accordance with current company policy, standards, and procedures aligning recognised standards of good practice.
   Date: Ongoing for the duration of this Notice
2. Maintain enhanced (in addition to routine regulatory sampling) sampling for any tanks listed in Annex 1. This must include, as a minimum, colony counts (at 22°C), total coliforms and E. coli.
   Date: Ongoing for the duration of this Notice
3. For all tanks and process tanks where ingress is identified:
   a) Implement immediate mitigation measures to ensure public health is protected.
   b) Complete any remedial work required at the earliest opportunity.
   Date: Ongoing for the duration of this Notice
4. Ensure all regulatory sample taps and regulatory sample tap rooms or kiosks are kept clean and tidy, with no objective evidence of tap contamination from the local environment.
   Date: Ongoing for the duration of this Notice
5. Maintain proactive external site inspections, grounds maintenance, site security and asset maintenance, including periodic inspections of hatches, seals, redundant assets, sample taps, previous repairs, overflows, washouts, and air valves. Maintain suitable records of these inspections and any remedial work carried out, to ensure a robust audit trail.
   Date: Ongoing for the duration of this Notice
6. Maintain appropriate contingency plans (including liaison with relevant stakeholders as appropriate) to protect human health.
   Date: Ongoing for the duration of this Notice
7. Keep under review residual chlorine concentrations to ensure appropriate set points and trigger values are in place to prevent a deterioration of drinking water quality.
   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:

General

1. Review and update Annex 1 on at least an annual basis to ensure that any tanks outside of the 10-year cleaning and physical internal inspection frequency are included. Update the regulation 28(1) risk assessment as appropriate.
   Date: Ongoing for the duration of this Notice and annually by 31 May each year.
2. Within 3 months of the identification of a new tank requiring addition to Annex 1 (following a review completed under measure (b)1., update the programme of works that was developed in measure (b)4., (including cleaning, robust ingression testing, and completion of remedial work required) to include the physical internal inspection for the identified tank
   Date: Annually by 31 August

Internal Tank Inspection Procedure

3. Conduct a gap analysis of the company’s physical internal inspection procedure and flood testing procedure benchmarking against industry good practice.
   Date: Complete
4. Update the company’s procedures based on the findings of the gap analysis completed under measure (b)3.
   Date: Complete

Internal (physical entry) Inspections – for tanks listed in Annex 1

5. Develop a plan for the enabling works required to remove the tanks listed in Annex 1 from supply for a physical internal inspection, clean, flood test, and completion of any remedial work required.
   Date: Complete
6. Carry out a test isolation for Lane End and Kimberworth service reservoir and monitor the associated supply system to determine if there is sufficient resilience when the reservoir is taken out of service and any potential risks to water quality.
   Date: Complete
7. Complete the physical internal inspections, clean and completion of any required remedial work for the Lane End SR, Kimberworth SR, and Stansfield View SR Inlet Chamber. Maintain appropriate documentation of any remedial work completed.
   Date: Complete
8. Implement the programme of internal inspections developed in measure (b)5 (including any updates completed under measure (b)2) to completion. Maintain appropriate documentation of any remedial work completed.
   Date: 30 June 2025

Internal Tank Inspections – Through Process (Interstage) Tanks

9. Conduct a review of all of the Company’s through process (interstage) tanks to identify any tanks that are not currently included within a risk-based internal inspection programme. Conduct a desktop risk assessment to develop a risk-based programme of inspection for through process (interstage) tanks to include any tanks identified and the tanks listed in Annex 2.
   Date: Complete
10. Implement the programme of internal inspections developed in measure (b)9. to completion, including review of the risk-based inspection frequency following inspection.
    Date: 30 September 2025

Overflow, washout, and pipework arrangements

11. Complete the risk-based programme of inspections for all water treatment works sites to review overflow, washout and pipework arrangements. Develop a programme of work for permanent remedial work required. This must include:
    a) Confirmation of the pipework arrangements, identification of any redundant pipework or faults (e.g. valves letting by) and implement any required interim mitigation(s).
    b) Review of the risk of contamination from vermin and implement any interim mitigation(s) required.
    c) Review of the risk of ingress / contamination from surface water or backflow and implement any interim mitigation(s) required.
    Date: Complete
12. Following the review in measure (b)11. for all water treatment works, carry out any permanent remedial work required, including the removal or physical disconnection of redundant pipes.
    Date: 31 December 2024
13. Update any relevant schematics, as required following completion of measure (b)11.
    Date: 31 December 2024
14. Complete the programme of inspections for all service reservoirs to review overflow, washout and pipework arrangements. Develop a programme of work for permanent remedial work required. This must include:
    a) Confirmation of the pipework arrangements, identification of any redundant pipework or faults (e.g. valves letting by) and implement any required interim mitigation(s).
    b) Review of the risk of contamination from vermin and implement any interim mitigation(s) required.
    c) Review of the risk of ingress / contamination from surface water or backflow and implement any interim mitigation(s) required.
    Date: Complete
15. Following the review in measure (b)14. for all service reservoirs, carry out any permanent remedial work required, including the removal or physical disconnection of redundant pipes, using a risk-based approach.
    Date: 31 December 2024
16. Update any relevant schematics, as required following completion of measure (b)14.
    Date: 31 December 2024

External Inspections for Tanks

17. Review, revise and update the company’s risk-based external integrity check procedure. This must include (but not be limited to):
    a) Assessment of overflow protection (whether protection is in place and functioning satisfactorily) and an escalation procedure if mitigation or remedial action is required.
    b) Assessment of the risk of contamination from vermin on site.
    c) An improved method for recording and tracking completion of the external integrity checks.
    d) An improved method for action tracking and escalation when actions are identified through completion of the checks.
    Date: Complete
18. Implement the revised external integrity check procedure developed in (b)17. and train all relevant personnel on the procedure and implement a ‘business as usual’ forward-reaching programme of reviewing the procedure and training staff on the procedure and any procedural updates.
    Date: Complete

(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: Complete
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 any tanks or process tanks, 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 a summary report of the findings of the gap analysis as required in measure (b)3.
   Date: Complete
3. Provide the company’s updated internal inspection and flood testing procedures.
   Date: Complete
4. Provide the risk-based plan and schedule of works for completing the physical internal inspection, clean and flood testing of the tanks (service reservoirs and contact tanks) listed in Annex 1.
   Date: Complete
5. Confirm completion of the test isolations of Lane End and Kimberworth service reservoirs.
   Date: Complete
6. Confirm completion of the physical internal inspections for the tanks listed in Annex 1. Provide evidence of completion of the physical internal inspection, clean, flood test and completion of any remedial work required.
   Date: Complete
7. Confirm completion of the review of all through process tanks and provide the risk-based plan and schedule of works for completing the internal inspection and clean for all through process tanks listed in Annex 2 and a list detailing the risk-based inspection frequency for all through process tanks.
   Date: Complete
8. Confirm completion of the risk-based programme of overflow, washout and pipework arrangement inspections at all water treatment works, as specified in measure (b)11.
   Date: Complete
9. Provide details of any interim mitigations implemented and the programme of work for permanent remedial work required at water treatment works, as specified in measure (b)11.
   Date: Complete
10. Confirm completion of the risk-based programme of overflow, washout and pipework arrangement inspections at all service reservoirs, as specified in measure (b)14.
    Date: Complete
11. Provide details of any interim mitigations implemented and the programme of work for permanent remedial work required at service reservoirs, as specified in measure (b)14.
    Date: Complete
12. Confirm completion of all permanent remedial work including the removal or physical disconnection of redundant pipes at water treatment works and service reservoirs, as specified in measures (b)12. and (b)15.
    Date: 31 January 2025
13. Confirm the update of any relevant schematics as specified in measures (b)13. and (b)16.
    Date: 31 January 2025
14. Confirm completion of the review of the company’s risk-based external integrity check procedure and provide the updated procedure, including evidence of training relevant personnel.
    Date: Complete
15. For any Annex 1 tank where a physical internal inspection, flood test, clean, and any required remedial work has been completed under (b)8. in advance of 31 October 2025, submit evidence demonstrating completion with an accompanying regulation 28(1) report for the tank and an updated Annex 1 list for this notice.
    Date: Annually by 31 May each year.
16. For any Annex 2 tank where an internal inspection, clean and any remedial work required (including physical entry if required) has been completed under (b)10. in advance of 31 October 2025, submit evidence demonstrating completion with an accompanying regulation 28(1) report.
    Date: Annually by 31 May each year.
17. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: Complete
18. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
19. 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
20. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 October 2025

Further Details of this Notice:

4. Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
5. 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.
6. 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

Nick Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
22 December 2023
Reference: YKS-2021-00002 v2