Current improvement programmes

Notice of Regulation: Maidenhead (College Avenue) Water Treatment Works




Assets affected:
Maidenhead (College Avenue) Supply system (Y219)

Legal Instrument Database Reference number: LI/SEW/2018/00016


  1. Has received a report from South East Water (the “Company”) dated 01 November 2017 (the “Report”) which states that there is or has been a significant risk of supplying water from Maidenhead (College Avenue) 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 requirement:

For risks associated with:

  • Chromium


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

Date: Until new treatment is installed and commissioned.

  1. Increased operational monitoring for chromium in the catchment and at Maidenhead College Avenue treatment works.
  2. Commence investigation of the source/s of Chromium within the catchment.
  3. Blending of the raw water sources to manage the final water chromium concentrations to ensure that levels in the final water comply with the current standard as defined in the Water Quality Regulations 2016 (as amended). The company should give regard to levels of Chromium 6 as defined in the DWI guidance and take action where levels are recorded above 3µg/l.

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

  1. Chromium water treatment pilot trials to be carried out to identify a suitable treatment option.
    Date: By 31 December 2022
  2. Planning and Design of final option.
    Date: By 31 March 2024
  3. Installation of Chromium removal treatment at Maidenhead (College Avenue) WTWs.
    Date: By 31 March 2025
  4. Continuation of catchment investigation and management to minimise levels of chromium reaching sources.
    Date: Until 31 March 2025
  5. In an appropriate maintenance regime for the chromium removal plant.
    Date: 31 April 2025
  6. Put in place training and associated procedures for ensuring the ongoing competence of staff charged with operating, maintaining and repairing the removal plants.
    Date: 31 April 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 to include:
    Date: For the duration of the notice
    • Pre-completion of the treatment solution sampling at a minimum weekly frequency of the raw and treated water for Chromium.
    • Post-completion of treatment solution sampling at a minimum weekly frequency of the raw, post-chromium removal stage and final water for Chromium

(d) N/A

(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:
    Date: Beginning January 2019
    • Provide a report regarding the audit strategy defined in (c)1.
      Date: 1 September 2019
    • Completion of the pilot trials in (b)1.
      Date: 31 January 2023
    • Following completion of the planning and design stage in (b)2.
      Date: 31 April 2024
    • Following completion of the installation of the chromium removal process in (b)3, maintenance program in (b)5 and training procedure in (b)6.
      Date: 31 April 2025
    • Following completion of catchment characterisation project to establish sources of Chromium within the catchment in (b)4.
      Date: 31 April 2025
  2. Review the risk assessment for Maidenhead (College Avenue) Supply System (Y219) as required by Regulation 27(4) and subsequently submit a revised regulation 28 report accompanied by a signed board level declaration.
    Date: 30 June 2025
  3. Submit a satisfactory completion report.
    Date: 31 May 2026

Failure by the Company to comply with this Notice may result in enforcement proceedings under section 18 of the Act.

Signed by authority of the Secretary of State
Milo Purcell
Deputy Chief Inspector
04 July 2019
DWI ref: LI/SEW/2018/00016
Version 1