Hafren Dyfrdwy Cyfyngedig – Service Reservoirs and Treated Water Tanks Inspections

Notice under regulation 28(4) of the Water Supply (Water Quality) Regulations 2018

Reference: HDC-2021-00002

Version Number: 3

Water undertaker as appointed under section 6 of The Water Industry Act 1991 (as amended): Hafren Dyfrdwy Cyfyngedig, with registered number 03527628 (hereinafter called ‘the Company’). 

Assets Affected:

• The chlorine contact tanks, service reservoirs, and treated water tanks (hereafter collectively referred to as ‘tanks’) used to supply water for regulation 4(1) purposes within the Company’s supply region.

Details of this Notice:

1. The Drinking Water Inspectorate (‘the Inspectorate’) has received multiple regulation 28(1) reports of the Water Supply (Water Quality) Regulations 2018 (‘the Regulations’) from the Company dated between 2019 and 2021, which state that there is or has been a significant risk of supplying water from its tanks (and associated assets as applicable) that could constitute a potential danger to human health.
2. Consequently, this Notice is served on the Company by the Inspectorate on behalf of the Welsh Ministers, under regulation 28(4) for the assets listed above, for risks associated with:

Description of Risk	Hazard/ Hazardous Event/ Parameter	Hazard ID
To address the risk of ingress contamination and microbial growth.	Total Coliforms (confirmed)	For example: R0001-377-S-H035-C001-23P
To address the risk of ingress contamination and microbial growth.	E. coli (confirmed)	For example: R0001-377-S-H035-C002-23Q
To address the risk of ingress contamination and microbial growth.	Clostridium perfringens (confirmed)	For example: R0001-377-S-H035-C003-2Q2
To address the risk of ingress contamination and microbial growth.	Colony counts at 22°C	For example: R0001-377-S-H035-C007-2C0
To address the risk of ingress contamination and microbial growth.	Residual disinfectant – Total Chlorine	For example: R0001-377-S-H047-C009-161
To address the risk of ingress contamination and microbial growth.	Residual disinfectant – Free Chlorine	For example: R0001-377-S-H047-C010-1R3

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 in accordance with company policy, standards, and procedures, aligning with recognised standards of good practice.
   Date: Ongoing for the duration of this notice.
2. Carry out investigatory sampling in response to any microbiological exceedances.
   Date: Ongoing for the duration of this notice.
3. Maintain risk based enhanced (in addition to routine regulatory sampling) sampling for any tanks listed in Annex 1 and identified as Priority 1 in Risk Based Approach. This must include, as a minimum, colony counts, E. coli, Clostridium perfringens and coliforms.
   Date: Ongoing for the duration of this notice.
4. Maintain proactive external site inspections, grounds maintenance, site security and asset maintenance. This must include periodic inspections of hatches, seals, redundant assets, sample taps, overflows, washouts, and air valves.
   Date: Ongoing for the duration of this notice.
5. Maintain appropriate contingency plans (including liaison with relevant stakeholders as appropriate) to protect human health.
   Date: Ongoing for the duration of this notice.
6. 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.
7. Maintain records and evidence of the identification, decision making, and completion of remedial work on all tank cells, to ensure a robust audit trail.
   Date: Ongoing for the duration of this notice.
8. Maintain an inspection and cleaning programme for all tanks in the Company’s supply region, including the use of the flood testing methodology detailed in the audit strategy (c)1. Carry out remedial works as required.
   Date: Ongoing for the duration of this notice.
9. Ongoing review of Risk Based Audit following implementation.
   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. Carry out an optioneering study to determine required enabling work for the isolation of the tanks listed in Annex 1.
   Date: Complete
2. Develop a programme of works (that includes cleaning, robust ingression testing (e.g. flood/ inundation) and completion of any tank remedial work required), using a risk-based approach, to carry out physical internal inspections of all tanks listed in Annex 1.
   Date: Complete
3. Review Annex 1 on at an annual basis to ensure that all tanks that have not been cleaned and physically internally inspected in the last 10 years or more, are identified within the Annex. Update the regulation 28(1) risk assessment as appropriate.
   Date: Annually by 31 May each year.
4. Within 3 months of the identification of a new tank requiring addition to Annex 1 (following a review completed under measure (b)3., update the programme of works (that includes cleaning, robust ingression (e.g. flood / inundation) testing and completion of any remedial work required) to include the physical internal inspections for the identified tank.
   Date: Annually by 31 May each year.
5. Complete the programme of physical internal inspections developed in (b)2. (including any updates completed under measure (b)4. to completion. Maintain appropriate documentation of any remedial work completed.
   Date: 29 February 2024
6. Conduct a critical review of the effectiveness of the Company’s scheduling and delivery of internal inspections of tanks. Identify measures (as required) to address the findings of the critical review.
   Date: Complete
7. Implement the measures identified under (b)6. above.
   Date: Complete
8. Develop a risk-based approach to determine the cleaning and physical internal inspection frequency of all DSR, to include as a minimum: Time since last inspected; Date of construction/age; Materials of construction/tank design; Water quality history (to include as a minimum E. coli, coliforms, and colony counts); Turnover and tank hydraulics; Points of potential ingress (hatches, seals, redundant assets, overflows, washouts, and air valves); Sample tap condition, tapping points, sample lines and material and any other risks related to individual tanks.
   Date: 31 January 2024
9. Implement the risk-based approach to cleaning and physical internal inspections of all DSR within the Company’s supply area, developed under measure (b)8.
   Date: 31 January 2024
10. Develop and implement a risk-based approach to determine the cleaning and physical internal inspection frequency for all contact tanks and treated water storage tanks.
    Date: 31 December 2024

(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). To include:
   • A methodology for robust flood testing.
   • The frequency for the enhanced monitoring programme of assets listed in Annex 1.
   • The frequency of proactive inspections carried out in line with measure (a)4.
     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 chlorine contact tanks, service reservoirs, and treated water 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 report summarising the outcomes of the Optioneering Study produced as required in measure (b)1.
   Date: Complete
3. Submit the programme of work for the physical internal inspection for tanks listed in Annex 1 as required under measure (b)2.
   Date: Complete
4. Submit a list of any newly identified tanks under measure (b)3. For any tanks listed in Annex 1, completed in advance of 31 January 2024, submit evidence demonstrating satisfactory completion of the internal inspection, flood testing, and any remedial work completed with an accompanying regulation 28(1) report for the tank and an updated Annex 1 list for this notice.
   Date: Annually by 30 June each year.
5. Submit any updated programme of works for the physical internal inspection of any tanks identified under measure (b)3. as required under measure (b)4.
   Date: Annually by 30 September each year.
6. Outline the findings of the critical review and any resulting identified measures (as required under measure (b)6. and confirm the TBC dates for the implementation of measures required for New Hall DSR and Cinders DSR.
   Date: Complete
7. Confirm completion of measure (b)7.
   Date: Complete
8. Provide the risk-based approach for DSR inspections developed under measure (b)8. and confirm implementation of this risk-based approach to cleaning and internal inspections, as required under measure (b)9.
   Date: 29 February 2024
9. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
   Date: Complete
10. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
11. 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.
12. Submit a satisfactory completion report, including evidence of Risk Based Approach for contact tanks and water storage tanks accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 28 February 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 Welsh Ministers, 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

Nicholas Adjei
Deputy Chief Inspector, on behalf of the Welsh Ministers
8 February 2024
Reference: HDC-2021-00002 v3