Current improvement programmes

Notice of Regulation: Halling GS Works




Assets affected:
T324T08 Halling 6 Bore New Treated (Greensand)
Z322 Halling Water Supply Zone
Z306 Forstal Water Supply Zone

DWI Reference number: SEW-2018-00011


  1. has received a report from South East Water Ltd (the “Company”) dated 01 September 2018 (the “Report”) which states that there is or has been a significant risk of supplying water from Halling GS Works that could constitute a potential danger to human health and could be unwholesome.
  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:

  • Failure to meet requirements of Regulation 26, inadequate disinfection, due to a failure to demonstrate that disinfection contact time is met under all conditions.
  • Residual Disinfectant- Free
  • Residual Disinfectant- Total
  • Microbiological


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

  1. Optimisation of all existing treatment processes.
    Date: Ongoing for the duration of the notice.
  2. Operation of all processes within defined normal operating ranges with appropriate triggers, responses and contingency procedures.
    Date: Ongoing for the duration of the notice.
  3. Online turbidity and chlorine monitoring with appropriate alarms and failsafe shutdown.
    Date: Ongoing for the duration of the notice.
  4. Enhanced and large volume operational monitoring for microbiological parameters at Halling GS works and at the downstream commercial property supplied.
    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 interim monitoring on a suitable downstream location after disinfection to provide information for the verification of disinfection.
    Date: By 30 November 2018 and until completion of (b)3.
  2. The Company shall undertake an investigation of the existing disinfection system and confirm a programme of work to provide adequate disinfection under all circumstances and flow rates and include the following:
    Date: Completed
    • The point in the treatment process whereby disinfection is achieved (the point of disinfection) must be clearly defined.
    • The final sample point must be located at the end of the treatment process and be representative of water leaving the treatment process.
    • The disinfection system must take into account flow dynamics through the treatment works and contact main, and this must be established using appropriate techniques.
    • The disinfection system must provide safeguards such as automatic shutdown or failsafe systems to prevent untreated or partially treated water entering into supply.
    • Installation of monitoring for turbidity and chlorination to provide continuous verification of disinfection.
    • Provide clearly defined critical control points, and real time evidence that the target chlorine contact time is achieved.
  3. Install (or modify the existing) and commission the chosen disinfection system as defined by (b)2.
    Date: 31 March 2022
  4. Review the site-specific Disinfection Policy with associated site-specific procedures and report revisions of the document to the Inspectorate.
    Date: 31 March 2022
  5. Update the Site Operating Manual and remove all out of date material from circulation.
    Date: 31 March 2022
  6. Provide adequate training to operators as part of the commissioning process and for any revision of the Site Operating Manual completed under (b)5.
    Date: 31 March 2022

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

  1. Define a strategy for auditing the effectiveness of the above measures.
    Date: Completed
  2. Implement the audit strategy outlined in (c)1. above.
    Date: Until the revocation of this Notice.

(d) not to supply water for regulation 4(1) purposes from Halling GS Treatment Works

  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 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:
    • Provide a report on completion of (b)1.
      Date: Complete
    • Provide annually a summary of results from the interim monitoring from (b)1 including any subsequent actions taken.
      Date: Annually by 31 January until the completion of (b)3.
    • Provide a design specification for the proposed disinfection scheme described in (b)2 with dates for commissioning and completion of work.
      Date: Complete
    • Submit a report on completion of the commissioning or modification of the chosen disinfection system as defined by (b)iii with an updated site-specific Disinfection Policy required under measure (b)4 and evidence of completed training required under measure (b)6.
      Date: 30 April 2022
    • Report to confirm details of the strategy for auditing the effectiveness of the measures as specified in (c)1.
      Date: Complete
  2. Review the risk assessment for Halling GS works as required by regulation 27(3) and subsequently submit a revised regulation 28 report accompanied by a signed board level declaration.
    Date: From time to time as required and by 31 May 2022
  3. Submit a satisfactory completion report.
    Date: 30 April 2023

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
30 November 2020
DWI ref: SEW-2018-00011
Version 2