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United Utilities Water Limited – AMP8 Ridgegate WTW Taste and Odour

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

Reference: UUT-2023-00007

Version Number: 1

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:

Asset Name

Reference

Ridgegate WTW

T041

Ridgegate

Z309

Table 1: List of assets affected and associated reference numbers

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 17 February 2023, which states that there is or has been a significant risk of supplying water from Ridgegate 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

Consumer acceptability (taste and odour)

Odour

T041A003245278

C041aA003267038

Consumer acceptability (taste and odour

Taste

T041A004245278

Consumer acceptability (taste and odour

Geosmin

T041F050245278

C041aF050267038

Consumer acceptability (taste and odour

2 Methyl Iso Borneol

T041F051245278

C041aF051267038

Table 2: 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. Continue catchment management measures including working in partnership with all sectors managing land and inputs on catchment to raise awareness and reduce nutrient loading where practicable.
    Date: Ongoing for the duration of this Notice
  2. Maintain existing catchment initiatives with external bodies such as: Defra, Reservoir Water Management Research group.
    Date: Ongoing for the duration of this Notice
  3. Maintain enhanced monitoring of raw water sources for geosmin and 2-methylisoborneol (2-MIB).
    Date: Ongoing for the duration of this Notice
  4. Maintain and operate existing works treatment in accordance with company standards.
    Date: Ongoing for the duration of this Notice
  5. Maintain action trigger levels and appropriate action response as detailed in Catchment and Process Taste and Odour Mitigation Plan for Ridgegate WTW.
    Date: Ongoing for the duration of this Notice
  6. Continue catchment inspections to protect water sources from pollution, loss of yield, or other adverse effects arising from activities within the catchment areas in line with catchment monitoring plan.
    Date: Ongoing for the duration of this Notice
  7. Ongoing review of Catchment and Process Taste and Odour Mitigation Plan for Ridgegate WTW and update where required.
    Date: Ongoing for the duration of this Notice
  8. Review the risk assessment for Ridgegate WTW and supply system as required by regulation 27(4).
    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. Review Catchment and Process Taste and Odour Mitigation Plan for Ridgegate WTW and update where required.
    Date: 30 June 2024
  2. Investigation into potential sources of geosmin in raw water, pathways and the effectiveness of mitigation in the catchment as agreed through the AMP8 WINEP programme.
    Date: 30 April 2027
  3. Installation of new granular activated carbon (GAC) contactors at Ridgegate WTW.
    Date: 30 September 2029
  4. Complete training of all operators in the new solution and update of all the relevant Quality Assurance procedures.
    Date: 31 December 2029

(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 June 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 Ridgegate 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. Provide report on review of Catchment and Process Taste and Odour Mitigation Plan for Ridgegate WTW.
    Date: 31 July 2024
  3. Provide a report to confirm completion of catchment investigations as defined in step (b)2.
    Date: 31 May 2027
  4. Provide a report on the completion of the installation of the GAC contactors as defined in step (b)3.
    Date: 31 October 2029
  5. Provide a report on the completion of the training of operators and update of all QA procedures as defined in step (b)4.
    Date: 31 January 2030
  6. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 31 July 2024
  7. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  8. 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
  9. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 October 2030

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
30 April 2024
Reference: UUT-2023-00007

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