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South West Water Limited – Water Quality Monitoring and Control Prewley WTW

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

Reference: SWB-2024-00003

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): South West Water Limited, with registered number 02366665 (hereinafter called ‘the Company’).

Assets Affected:

  • Prewley WTW T3832F

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 21 October 2020, which states that there is or has been a significant risk of supplying water from Prewley WTW (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


Potential risks of inadequate disinfection or uncompliant water leaving treatment works.

Hydrogen ion (pH) -A006

12539


Potential risks of inadequate disinfection or uncompliant water leaving treatment works.

Turbidity – A002

12542


Potential risks of inadequate disinfection or uncompliant water leaving treatment works.

E. coli – C002

12497


Potential risks of inadequate disinfection or uncompliant water leaving treatment works.

Total Coliforms -C001

12175

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. Review the risk assessment of short-term process outages:
    • Identifying the risks and determine the mitigations required to protect water quality as a result of processes being removed and/or returned to supply.
    • Ensure such risk assessments are reviewed and kept up to date.
      Date: Ongoing for the duration of this Notice
  2. Adherence to site specific start-up and shutdown procedures.
    Date: Ongoing for the duration of this Notice
  3. Adherence to company water quality investigational sampling procedures to ensure compliance with the requirements of regulations 10, 18 and 19.
    Date: Ongoing for the duration of this Notice
  4. Operation of all processes within defined operating ranges with appropriate and documented, triggers and responses where deviations occur.
    Date: Ongoing for the duration of this Notice
  5. Maintain instrument maintenance, calibration and verification to ensure the treatment works operate to the requirements of the Site-Specific Disinfection Policy.
    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. Install and commission duplicate chlorine, duplicate turbidity, and duplicate pH instrumentation post contact tank.
    Date: 30 June 2027

(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: 30 November 2024
  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 Prewley WTW, 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 audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 31 December 2024
  3. Provide evidence of the installation, commissioning and operation of the instruments, as specified in measure (b)1.
    Date: 31 July 2027
  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: 30 September 2027

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
2 September 2024
Reference: SWB-2024-00003 v1

 

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