Severn Trent Water Limited – Service Reservoirs and Treated Water Tanks Inspections Combined

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

Reference: SVT-2024-00003

Version Number: 2

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Severn Trent Water Limited, with registered number 02366686 (hereinafter called ‘the Company’).

Assets Affected:

• All 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 by the Company.

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 21 October 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 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:

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.

Description of Risk	Hazard/ Hazardous Event/ Parameter	Hazard ID
To address the potential risks of ingress and microbial re-growth.	Coliform bacteria	For example: R0330-938-S-H035-C001-23P
To address the potential risks of ingress and microbial re-growth.	Escherichia coli (E. coli)	For example: R0330-938-S-C111-C002-23Q
To address the potential risks of ingress and microbial re-growth.	Clostridium perfringens	For example: R0330-938-S-C111-C004A-2YX
To address the potential risks of ingress and microbial re-growth.	Enterococci	For example: R0330-938-S-C111-C003-2Q2
To address the potential risks of ingress and microbial re-growth.	Colony Counts	For example: R0330-938-S-H035-C007-2C0
To address the potential risks of ingress and microbial re-growth.	Residual Disinfectant – Total Chlorine	For example: R0330-938-S-H047-C009-161
To address the potential risks of ingress and microbial re-growth.	Residual Disinfectant – Free Chlorine	For example: R0330-938-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 current company policy, standards and procedures, that align to 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
10. Implement the measures identified following the critical review of the effectiveness of the Company’s scheduling and delivery of internal inspections of tanks.
    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. Develop a programme of works (that includes cleaning, robust ingression testing (e.g. flood/inundation), enabling works 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
2. Review Annex 1 on at least a biannual basis to ensure that all tanks that have not been cleaned and physically internally inspected in the last 10 years, are identified within Annex 1, unless included in a site-specific notice. Update the regulation 28(1) risk assessment as appropriate.
   Date: Biannually by 31 May and 30 November
3. Within 3 months of the identification of a new tank requiring addition to Annex 1 (following a review completed under measure (b)2), 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: Biannually by 31 August and 28 February
4. Complete the programme of works developed in (b)1. (Including any updates completed under measure (b)3) to completion. Maintain appropriate documentation of any remedial work completed.
   Date: 31 July 2026
5. 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: Complete
6. Implement the risk-based approach to cleaning and physical internal inspections of all tanks within the company’s supply area, developed under measure (b)5.
   Date: Complete
7. 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, following same criteria as DSR in (b)5.
   Date: 31 December 2024
8. Upon the discovery of active ingress into any treated water storage assets
   a) Implement immediate short term mitigation measures to ensure public health is protected.
   b) Remove the asset from supply and complete the required remedial works.
   Where the company are unable to meet the two requirements above, devise and implement a solution to remove the asset from supply at the earliest opportunity.
   Date: Ongoing for the duration of this notice

(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 Company’s 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. Submit the programme of work for the physical internal inspection for tanks listed in Annex 1 as required under measure (b)1.
   Date: Complete
3. Submit a list of any newly identified tanks to be included in Annex 1, as required under measure (b)2. For any tanks listed in Annex 1, completed in advance of 31 July 2026, submit evidence demonstrating satisfactory completion of the internal inspection, ingression (e.g. inundation/flood) testing, and any remedial work completed with an accompanying regulation 28(1) report for the tank and an updated Annex 1 for this notice.
   Date: Biannually by 30 June and 31 December
4. Submit any updated programme of works for the physical internal inspection of any tanks identified under measure (b)2.
   Date: Biannually by 30 September and 31 March
5. Confirm completion of the programme of works for all tanks listed in Annex 1.
   Date: 31 August 2026
6. Provide the risk-based approach for DSR inspections developed under measure (b)5. and confirm implementation of this risk-based approach to cleaning and internal inspections, as required under measure (b)6.
   Date: Complete
7. Provide the risk-based approach for contact tank and treated water storage tank inspections and confirm implementation of this risk-based approach to cleaning and internal inspections, as required under measure (b)7.
   Date: 31 January 2025
8. Where active ingress has been found and the company are unable to take the asset out of supply immediately, the company shall submit an action plan to detail how the company intends to mitigate the risks associated with ingress in the medium to long term.
   Date: As required for the duration of the notice, within 2 months of discovering ingress.
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 accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 August 2027

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

Nicholas Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
5 August 2024
Reference: SVT-2024-00003 V2