Notice of Regulation: Oldfield – Disinfection By-products



YORKSHIRE WATER: Oldfield AMP7 disinfection by products

Oldfield WTW
Keighley Water Supply System (YSAI00130869)

Legal Instrument Database Reference number: YKS-2018-00003


  1. has received a report from Yorkshire Water (the “Company”) dated 23rd December, 2017 which states that there is a future significant risk of supplying water from Oldfield Water Treatment 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 that it must satisfy the following requirements:

For risks associated with:

  • Disinfection by-products (THMs and HAAs), to secure compliance with Regulation 26(1)(b) and Regulation 26 (2)(a)


(a) to maintain the following measure[s] for the period specified [in each case]

Date: For the duration of this Notice

  1. Continue to regularly monitor raw water trends for the parameter colour, and keep under review DOC trends from on-line monitoring (UV254)
  2. Optimise existing processes to minimise the risk of DBP formation
  3. Regularly monitor treated, stored, and distributed water for DBPs (THMs and HAAs) – additional samples to be bi-monthly August to November, monthly for the remainder of the year
  4. Continue to review opportunities for catchment management activities with stakeholders to implement protective measures and reduce the risk of deterioration of raw water quality, and implement those measures agreed with the EA as part of the AMP7 WINEP.

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

  1. Regularly monitor treated water, water within key service reservoirs, and distributed water for DBPs (THMs and HAAs)
    Date: For the duration of this notice
  2. Regularly review the level of residual DOC remaining from raw water following the existing processes and ensure its removal is optimised (including the optimisation of coagulation pH and coagulant dose, and the minimisation of RGF turbidity) Regulatory review WTW performance within Water Quality and Production Operational teams to maintain optimised conditions.
    Date: From 30 April, 2019 for the duration of this notice
  3. Confirm the chosen solution and provide outline design for additional removal of DOC from the raw water inlet, following engineering and process reviews and, where required, pilot trials
    Date: 30 October 2022
  4. Provide a detailed design of the proposed solution
    Date: 31 June 2023
  5. Install, commission, and verify through testing, the chosen solution
    Date: 30 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 above measures. To include:
    Date: 31 December, 2019
    • Sampling and data analysis for DBPs (THMs & HAAs) with a focus on ex-works and distributed water
    • Development of an auditable means by which the Company will demonstrate minimisation of DBP risks at the upgraded works under all raw water conditions
  2. Implement the audit strategy outlined in (c)1 until revocation of this Notice.
    Date: 01 April, 2020

(d) not to supply water for regulation 4(1) purposes from Oldfield WTW unless the conditions specified below are satisfied

  1. That all reasonable operational steps have been taken to ensure that water that is not compliant with the requirements of regulations 4 and 26, or that is potentially harmful to consumers, is prevented from entering supply.
    Date: For the duration of this notice

(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:
    • Completion of investigations, pilot trials and development of outline design
      Date: 30 November 2022
    • Completion of detailed design of the proposed solution
      Date: 30 August 2023
    • Completion of Installation and commissioning, of the chosen solution
      Date: 30 April 2025
  2. Review the risk assessment for Oldfield WTW as required by Regulation 27(4) and subsequently submit a revised regulation 28/29 report accompanied by a signed board level declaration.
    Date: 30 May, 2025
  3. Submit a satisfactory completion report
    Date: 31 April, 2026

Failure by the Company to comply with this Notice may result in enforcement proceedings under section 18 of the Act. [Further contravention of the regulation 28(4)(d) or 29(4)(d) requirement in this Notice is an offence and a person guilty of the offence shall be liable on conviction to a fine]1.

Signed by authority of the Secretary of State
Milo Purcell
Deputy Chief Inspector
2 April 2019
DWI ref: LI/YKS/2018/00003
Version 1

1 DWI use only: Insert this wording only if the Notice contains condition 2(d) i.e. if it prohibits the supply of drinking water or prohibits supply unless specified conditions are satisfied.

Back to top