United Utilities Water Limited – Prescot North and South Service Reservoirs

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

Reference: UUT-2021-00002

Version Number: 2

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): United Utilities Water Limited, with registered number 02366678 (hereinafter called ‘the Company’).

Assets Affected:

  • R432 Prescot North Service Reservoir
  • R433 Prescot South Service Reservoir
  • Z120 Lightshaw
  • Z121 Ashton
  • Z125 Haydock
  • Z176 Liverpool CTM 36 inch
  • Z178 Liverpool City Centre
  • Z179 Aubrey
  • Z184 Toxteth
  • Z185 Mossley
  • Z186 Wavertree
  • Z187 Childwall
  • Z188 Huyton East
  • Z189 Liverpool CTM 40 inch
  • Z190 Liverpool CTM 44 inch
  • Z191 Woolton

Details of this Notice:

  1. The Drinking Water Inspectorate (‘the Inspectorate’) has received a regulation 28(1) report of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated between 15 April 2019 and 28 January 2021, which states that there is or has been a significant risk of supplying water from Prescot North and South 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

Microbiological risks associated with risk of potential ingress. Risks of coliforms associated with water age.

E. coli

(19 June 2019)

(28 January 2021)

R432 C002295123

R433 C002295124

Microbiological risks associated with risk of potential ingress. Risks of coliforms associated with water age.

Total Coliforms

(19 June 2019)

(28 January 2021)

R432 C001295123

R433 C001295124

Microbiological risks associated with risk of potential ingress. Risks of coliforms associated with water age.

Cryptosporidium

(20 May 2019)

R432 C111304658

R433 C111304659

Risks associated with water age.

Taste

(15 April 2019)

R432 A004295648

R433 A004295649

Risks associated with water age.

Odour

(15 April 2019)

R432 A003295648

R433 A003295649

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.
  1. 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. Maintain enhanced water quality sampling at Prescot North and South Service Reservoirs (SR) using flow cytometry.
    Date: Ongoing for the duration of this Notice
  2. Continuous maintenance and review of target chlorine residual and set points at Prescot North and South SRs.
    Date: Ongoing for the duration of this Notice
  3. Enhanced monitoring for coliforms, colony counts, and chlorine residuals within the downstream distribution system. Where there is a risk of cryptosporidium from ingress, cryptosporidium monitoring should be carried out.
    Date: Ongoing for the duration of this Notice
  4. Maintenance and checks of the flora and fauna at Prescot North and South SRs
    Date: Ongoing for the duration of this Notice
  5. Site security checks, operational equipment checks, and SR external inspection visits at Prescot North and South SRs.
    Date: Ongoing for the duration of this Notice
  6. Continuous review of turnover and chlorine residuals as part of the Drinking Water Safety Plan risk assessment for Prescot North and South SRs.
    Date: Ongoing for the duration of this Notice
  7. Manage SR levels based on demand and alarm set points to ensure turn-over is optimised.
    Date: Ongoing for the duration of this Notice
  8. Maintenance, calibration and verification of water level control system at Prescot North and South SRs.
    Date: Ongoing for the duration of this Notice
  9. Record and Monitor discolouration customer contacts at appropriate detail during each SR outage period within the ICC and as part of the weekly distribution operational maintenance strategy (DOMS) process.
    Date: Ongoing for the duration of this Notice
  10. Planned work risk assessments to be completed prior to start on site and presented to the Water Quality Risk Board (WQRB).
    Date: Ongoing for the duration of this Notice
  11. Development and trial of operational plans to control SR level during outage period with network contingency plans documented.
    Date: Ongoing for the duration of this Notice
  12. Additional turbidity monitoring on the outlet mains.
    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. Complete internal inspection (including robust flood test) and clean of the Prescot North and South SRs. Complete any remedial work required following the internal inspection of Prescot North and South SRs, before returning the SRs to service.
    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 Prescot North or South SR, 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. Confirm completion of internal inspection (including robust flood test) and clean Prescot North and South SRs. Confirm completion of remedial work required following the internal inspection.
    Date: Complete
  3. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: Complete
  4. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  5. 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
  6. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 July 2024

Further Details of this Notice:

  1. Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
  2. 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.
  3. 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
22 November 2023
Reference: UUT-2021-00002 v2

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