Current improvement programmes

Notice of Regulation: Sandown Shanklin Water Supply Works



SOUTHERN WATER SERVICES LTD: Sandown Shanklin Water Supply Works

TI017 – Sandown Shanklin WSW

DWI Reference: LI/SRN/2018/00020


  1. has received a report from Southern Water Services Ltd (the “Company”) dated 08 July 2019 (the “Report”) which states that there is or has been a risk of supplying water from Sandown Water Supply Works that could constitute a potential danger to human health.
  2. GIVES NOTICE to the Company under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended) that it must satisfy the following requirements:

For risks associated with:

  • Clostridium Perfringens
  • Cryptosporidium
  • E. coli
  • Enterococci
  • Lead
  • Manganese
  • No Supply
  • Pesticides
  • Total Coliforms


(a) to maintain the following measures for the period specified in each case:

  1. Establish and maintain in place until improvement works are completed such enhanced operational measures as necessary to ensure that consumers are protected and water supplied from the site is adequately treated and wholesome.
    Date: Ongoing for the duration of the Notice
  2. Enhanced monitoring (3 times per week) for Cryptosporidium on the raw and continuous on the treated water of both the Brading and Shanklin reservoir lines until validated UV is operational.
    Date: Ongoing for the duration of the Notice
  3. Daily enhanced monitoring for E.coli, coliforms, Clostridium and Enterococci microbiology from both the Brading and Shanklin final water sample points until validated UV is operational.
    Date: Ongoing for the duration of the Notice
  4. Enhanced monitoring of disinfection byproduct generation at both the treated sample point and all downstream treated water reservoirs until 12 months after UV installation.
    Date: Ongoing for the duration of the Notice
  5. Continuous monitoring of the XTN RGF stream (also known as Extended Stream) in order to review and optimise performance and backwash regime.
    Date: Ongoing for the duration of the Notice

(b) to review, revise and/or make operational the following measures, by the date specified below:

  1. Install and commission UV units on both the Brading and Shanklin lines.
    Date: COMPLETE
  2. Document and implement control procedures to manually enhance RGF drain down prior to washing.
    Date: COMPLETE
  3. Complete investigations into root cause of poor RGF drain down and implement corrective measures as required.
    Date: COMPLETE
  4. Investigate the performance of the RGFs and the design and performance of the lamella clarifiers and identify any corrective measures.
    Date: COMPLETE
  5. Investigate options to improve manganese removal.
    Date: COMPLETE
  6. Replace PACl storage tanks.
    Date: COMPLETE
  7. Replace all required valves on the GAC and introduce automated backwash cycle.
    Date: 31 December 2020
  8. Produce full Clear Water Tank replacement plans and design.
    Date: 31 December 2021
  9. Replace the wooden stop logs from the Contact Tank outlet weirs.
    Date: COMPLETE
  10. Confirm measures for manganese removal to be implemented in (b)12.
    Date: 31 December 2021
  11. Confirm measures for RGF and lamella performance to be implemented in (b)13.
    Date: 31 December 2021
  12. Replace Clear Water Tank and High Lift Pumps.
    Date: 30 September 2024
  13. Implement measures to improve manganese removal, as identified in step (b)6.
    Date: 31 December 2023
  14. Implement corrective measures as identified in step (b)4.
    Date: 31 December 2023
  15. Improve washwater lagoon discharge capability.
    Date: 31 March 2025
  16. Install orthophosphoric acid dosing.
    Date: 29 October 2021
  17. Replace MCC 2.
    Date: 31 March 2025
  18. Review current flood risk and implement remedial works to ensure suitable resilience
    Date: 31 March 2025
  19. Carry out power resilience assessment (ECM4007) and implement recommended actions
    Date: 31 March 2025

(c) to audit whether the measures have been effective by the following means:

  1. Define a strategy for auditing the effectiveness of the measures made operational above.
    Date: To be submitted two months after the Notice is served and resubmitted as the strategy evolves.

(d) not to supply water for regulation 4(1) purposes from Sandown Shanklin WSW

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 risk of supplying water that would constitute a potential danger to human health:

  1. Provide a progress report annually by 31 January and against the following milestones:
    • Installation of UV units.
      Date: COMPLETE
    • Identification of corrective actions for RGF drain down and confirmation of manual procedures to enhance RGF drain down.
      Date: COMPLETE
    • Completion of investigation into performance of RGFs and lamella clarifiers and outline of recommended actions.
      Date: COMPLETE
    • Outcome of investigation on manganese removal.
      Date: COMPLETE
    • Replacement of valves on GAC, introduction of automated backwash cycle and PACl storage tank replacement.
      Date: 31 January 2021
    • Clear Water Tank replacement plans and design.
      Date: 31 January 2022
    • Installation of orthophosphoric acid dosing.
      Date: 30 November 2021
    • Completion of Hazrev actions due by 2025.
      Date: 30 April 2025
  2. Review the risk assessment for Sandown Water Treatment Works as required by regulation 27(3) and subsequently submit a revised regulation 28 report accompanied by a signed board level declaration.
    Date: As required during the Notice and within 2 months of the completion of all work for each WSW.
  3. Submit a satisfactory completion report.
    Date: 30 April 2026.13 months after the completion of all measures in section (b)

Failure by the company to comply with this Notice may result in enforcement proceedings under section 18 of the Water Industry Act 1991.

Signed by authority of the Secretary of State
Milo Purcell
Deputy Chief Inspector
12 March 2021
DWI Reference: LI/SRN/2018/00020
Version 3