South East Water Limited – Woodgarston Treatment Works, Nitrate Risk

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

Reference: SEW-2018-00015

Version Number: 2

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): South East Water Limited, with registered number 02679874 (hereinafter called ‘the Company’).

Assets Affected:

Asset Name

Asset Reference

Woodgarston Treatment Works


Woodgarston Supply Zone


Whitedown Water Supply Zone


Cliddesden Water Supply Zone


Table 1: List of assets affected and associated reference numbers

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 01 November 2017, which states that there is or has been a significant risk of supplying water from Woodgarston Treatment 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 nitrate.
  3. 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.


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

  1. Management of the borehole usage. Borehole No.1 is not in use due to the elevated nitrate concentrations.
    Date: until completion of measure (b)1.
  2. The Company will confirm that arrangements for blending are consistent with current industry best practice and all Drinking Water Inspectorate guidance and requirements of the Regulations.
    Date: until completion of measure (b)1.
  3. The Company will evaluate and determine the most suitable method to blend the source waters to reduce the nitrate concentration in the final water accordingly to ensure compliance with the regulations.
    Date: until completion of measure (b)1.
  4. Weekly water sampling of borehole and final waters for nitrate.
    Date: until completion of measure (b)1.
  5. Continuation of catchment management working with stakeholders to reduce input from sources, understand activities contributing to nitrate in catchment and put in place and maintain appropriate mitigations for areas at high risk.
    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 treatment at Woodgarston Treatment Works to mitigate the risk of nitrate. Commissioning must include the following to account for the changes made:
  • An appropriate maintenance regime for the nitrate treatment;
  • Full integration of the new processes into the site control and monitoring systems;
  • Updating of the Site-Specific Disinfection Policy and any associated site-specific procedures;
  • Updating of the Site Operating Manual and removal of all out-of-date material from circulation; and
  • Provisions of adequate training for all relevant personnel on the operation, repair and maintenance of the nitrate treatment and the revised procedures, policies and manual.
    Date: 30 November 2022

(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). To include:
  • Pre-completion of the treatment solution, sampling at a weekly frequency of the raw and treated water for nitrate.
  • Post-completion of the treatment solution sampling, sampling at a weekly frequency of the raw, post-nitrate removal stage and blended final water for nitrate.
    Date: Complete
  1. 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 Woodgarston Treatment Works, 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. Evidenced confirmation of the completion of measure (b)1.
    Date: 31 December 2022
  3. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: Complete
  4. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  5. 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
  6. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 December 2023

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).


Nicholas Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
09 November 2022
Reference: SEW-2018-00015 V2

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