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Notice of Regulation: South West Water – Scientific Investigations

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

South West Water Limited: Review and Revise Water Quality Monitoring, Control, and Investigations

Reference: SWB-2020-00010

Version Number: 4

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:

  • All water treatment works in the South West Water Limited supply region, excluding sites listed at Annex A.

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 2020, which state that there is or has been a significant risk of supplying water from treatment works in the South West Water Limited supply region (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


To address the potential risks of inadequate disinfection or uncompliant water leaving treatment works and ensure appropriate investigation into deteriorations in water quality.

Total Coliforms


To address the potential risks of inadequate disinfection or uncompliant water leaving treatment works and ensure appropriate investigation into deteriorations in water quality.

E. coli


To address the potential risks of inadequate disinfection or uncompliant water leaving treatment works and ensure appropriate investigation into deteriorations in water quality.

Aluminium
(Iron at Drift WTW only)


To address the potential risks of inadequate disinfection or uncompliant water leaving treatment works and ensure appropriate investigation into deteriorations in water quality.

Turbidity


To address the potential risks of inadequate disinfection or uncompliant water leaving treatment works and ensure appropriate investigation into deteriorations in water quality.

pH

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
  1. Adherence to site specific start-up and shutdown procedures.
    Date: Ongoing for the duration of this Notice
  2. 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
  3. 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
  4. 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. Carry out a gap analysis for the following at all water treatment works:
    • The availability of portable testing equipment, to include as a minimum, turbidity, chlorine, pH and conductivity
      Date: Complete
    • Continuous online turbidity monitoring equipment at critical control points.
      Date: Complete
    • Continuous online pH monitoring equipment at critical control points.
      Date: Complete
  1. Develop a strategy for the implementation, training and ongoing use at all water treatment works for portable testing equipment. To include as a minimum: turbidity, chlorine, pH, and conductivity at all water treatment works.
    Date: Complete
  2. Develop a strategy for the implementation, training and ongoing use at all water treatment works for continuous online turbidity monitoring equipment at critical control points.
    Date: Complete
  3. Develop a documented procedure to carry out scientific checks to verify abnormal monitor readings during a water quality event or near miss, including:
    • Checking the calibration of the instrument, following the manufacturer’s recommended procedure.
    • Taking measurements with portable or on-site analytical equipment, to verify readings.
    • If the portable or on-site analytical equipment readings indicate that the quality of water being supplied to consumers may be unwholesome, contemporaneous samples should be collected from appropriate sample points for laboratory analysis.
      Date: Complete
  1. Implement the strategy developed in measures (b)2 and (b)3. and implement the procedure developed in measure (b)4. To include:
    • Install and commission the online monitors as identified in measure (b)1.
    • Train relevant staff on the use of the portable and online monitors including the use of information for investigatory purposes and escalation triggers.
      Date: Complete
  1. Review, revise, and update Site Specific Disinfection Policies for all treatment works to ensure that a comprehensive overview of normal operating conditions and alarm settings at each works is detailed.
    Date: Complete
Online Aluminium Monitor Trial
  1. Install and commission multi-channel online residual aluminium monitors (of two different manufacturers) at the selected water treatment works.
    Date: Complete
  2. Develop a methodology for the trials of online residual aluminium monitors at the selected water treatment works to compare current operational monitoring against both types of online monitors (as well as comparison between the monitors).
    Date: Complete
  3. Complete a trial of the two types of multi-channel online aluminium residual monitors at the selected water treatment works (for a minimum of 1 year).
    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 any treatment works, 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 on the results of the gap analysis for measures outlined in measures (b)1.
    Date: Complete
  3. Provide the strategy developed in measure (b)2., including a summary of the implementation, training and ongoing use of portable testing equipment.
    Date: Complete
  4. Provide the strategy developed for the provision of continuous online monitoring with appropriate alarms and failsafe mechanisms, as specified in measure (b)3.
    Date: Complete
  5. Provide the procedure developed as specified in measures (b)4.
    Date: Complete
  6. Confirm and evidence the installation and commissioning of online monitors, as described in (b)5.
    Date: Complete
  7. Confirm the implementation of the strategy developed in (b)3. and the implementation of the procedure developed in (b)4.
    Date: Complete
  8. Confirm the review and reissue of site-specific disinfection policies (SSDPs). Provide a summary of the changes made for each SSDP updated annually for the relevant water treatment works.
    Date: Complete
  9. Confirm the installation and commissioning of the two types of multi-channel residual aluminium monitors at the selected water treatment works and provide methodology for comparing approach to current practice.
    Date: Complete
  10. Provide a report on the findings of the trial of two types of residual aluminium monitors at the selected water treatment works.
    Date: Complete
  11. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: Complete
  12. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  13. 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
  14. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 May 2025

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-2020-00010 v4

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