Southern Water Services Limited – AMP8 East Sussex Nitrate

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

Reference: SRN-2023-00008

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Southern Water Services Limited, with registered number 02366670 (hereinafter called ‘the Company’).

Assets Affected:

  • Patcham Water Supply Works – TS029
  • Mossy Bottom Water Supply Works – TS033
  • Brighton Supply System – Y007

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 24 August 2022 and 28 March 2023, which states that there is or has been a significant risk of supplying water from Mossy Bottom Water Supply Works and Patcham Water Supply Works (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 ID

Increasing nitrate in raw waters

Nitrate

44307

44121

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. Enhanced sampling and monitoring for nitrate (once available) of all high-risk raw water sources and associated final waters on a weekly basis to supplement the current regulatory treated water monitoring.
    Date: Ongoing for the duration of this Notice
  2. Report all exceedances of the nitrate parameter to the Local Authority and Health Protection team and agree further additional steps to protect public health as appropriate.
    Date: Ongoing for the duration of this Notice
  3. Report all regulatory exceedances of the standards for the nitrate parameter in mg/l NO3 to DWI as part of current monthly exception reporting process.
    Date: Ongoing for the duration of this Notice
  4. Carry out maintenance, validation and calibration of all online nitrate monitors installed, at sites covered by this notice, at the frequency outlined within company procedures.
    Date: Ongoing for the duration of this Notice
  5. Continue to follow the nitrate operating plan for Mossy Bottom and Patcham WSW.
    Date: Ongoing for the duration of this Notice
  6. Continue ongoing catchment management for Nitrate.
    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 enhanced source control at Mossy Bottom WSW
    Date: 31 December 2025
  2. Confirm locations and scope of additional nitrate mitigation measures. The notional solution scope is as follows:
    a) Installation of Ion exchange nitrate removal plant at Patcham WSW.
    Date: 31 March 2026
    b) Installation of Ion exchange nitrate removal plant at Mossy Bottom WSW.
    Date: 31 March 2026
  3. Complete installation and commissioning of nitrate mitigation measures as confirmed in (b)2.
    a) At Patcham WSW
    Date: 31 March 2029
    b) At Mossy Bottom WSW
    Date: 30 September 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: 31 March 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 Mossy Bottom WSW and Patcham WSW, 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 confirming the installation and commissioning of enhanced source control at Mossy Bottom WSW
    Date: 31 January 2026
  3. Provide a report confirming the scope and location of the nitrate mitigation measures at Patcham WSW and Mossy Bottom WSW identified in section (b)2.
    Date: 30 April 2026
  4. Provide a report confirming the completion of the installation and commissioning of the nitrate mitigation measures identified in section (b)3a. At Patcham WSW.
    Date: 30 April 2029
  5. Provide a report confirming the completion of the installation and commissioning of the nitrate mitigation measures identified in section (b)3b. At Mossy Bottom WSW.
    Date: 31 October 2029
  6. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 30 April 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
7 February 2024
Reference: SRN-2023-00008 v1

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