Notice of regulation: 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: 2

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 states 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, to address the risk of ingress, contamination and microbial growth. For risks associated with:

Hazard/ Hazardous event/ Parameter	Description of Risk
Total Coliforms (Confirmed)	To address the risk of ingress contamination and microbial growth.
E. coli (Confirmed)	To address the risk of ingress contamination and microbial growth.
Clostridium perfringens (Confirmed)	To address the risk of ingress contamination and microbial growth.
Enterococci (Confirmed)	To address the risk of ingress contamination and microbial growth.
Colony Counts at 22oC	To address the risk of ingress contamination and microbial growth.
Residual Disinfectant – Total Chlorine	To address the risk of ingress contamination and microbial growth.
Residual Disinfectant – Free Chlorine	To address the risk of ingress contamination and microbial growth.

Table 1: Table of the parameter(s) covered by this notice and the description of associated risks. 

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

The date given (the ‘date’) 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 enhanced sampling (in addition to statutory sampling) for any tanks listed in Annex 1. This must include, as a minimum colony counts, E. coli, and Total coliforms.  
   Date: Ongoing for the duration of this notice  

4. Maintain proactive external site inspections, grounds maintenance, site security and asset maintenance, including 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.  
   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: 30 September 2022 

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 August each year 

5. Implement 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: 31 January 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 measure 6 above.   
   Date: 30 September 2022

8. Develop a risk-based approach to determine the cleaning and physical internal inspection frequency for all tanks within the Company’s supply area.  
   Date: 31 December 2023 
   To include as a minimum: 
   • Time since last internal inspection;  
   • Date of construction and age;  
   • Materials of construction and tank design;  
   • Water quality history (to include as a minimum: E. coli, Total coliforms, and colony counts);  
   • Turnover and tank hydraulics;  
   • Chlorine residual trends;  
   • Findings of any recent ROV inspections and external inspections;  
   • Points of potential ingress (hatches, seals, redundant assets, overflows, washouts, and air valves);  
   • Sample tap condition, tapping points, sample lines and material;  
   • Any other risks related to individual tanks.  

9. Implement the risk-based approach to cleaning and physical internal inspections of all tanks within the Company’s supply area, developed under measure (b) 8.  
   Date: 31 January 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). 
   Date: Complete
   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. 

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 tanks listed in Annex 1 of this notice, 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: 

Provide a progress report annually by 31 January and against the following milestones: 

1. Provide a report summarising the outcomes of the Optioneering Study produced as required in measure (b) 1. 
   Date: Complete

2. Submit the programme of work for the physical internal inspection for tanks listed in Annex 1 as required under measure (b) 2.  
   Date: 31 October 2022 

3. 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 

4. 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 

5. 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 

6. Confirm completion of measure (b) 7.  
   Date: 31 October 2022 

7. Outline the risk-based approach 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 31 January 2024 

8. Submit the strategy for auditing the effectiveness of the measures, as specified in (c)1. 
   Date: Complete 

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 needs 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: 29 February 2024 

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 
25 August 2022 
Reference: HDC-2021-00002 (V2)