Current improvement programmes

Notice of Regulation: Sturminster Marshall/Shapwick Water Works




Site name and reference: Sturminster Marshall/Shapwick Works T33126200

Supply System name and reference: Shapwick (Zone 92) Y44000092

Legal Instrument Database Reference number: WSX-2018-00002


  1. has received a report from Wessex Water (the “Company”) dated 28 December 2017 (the “Report”) which states that there is or has been a significant risk of supplying water from Sturminster Marshall/Shapwick 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 2018 (as amended) that it must satisfy the following requirements:

For risks associated with:

  • Nitrate


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

Date: For the duration of notice

  1. Continuation of catchment management activities For the duration of notice
  2. Regular operation
    • Monitor/alarm systems
    • Maintain site operating procedures and training documentation
  3. Routine maintenance
    • Raw and treated nitrate monitors calibrated at a minimum monthly frequency
    • Monitors also re-calibrated following a water quality event or evidence of drift
      Raw and treated nitrate monitors serviced at a minimum six-month frequency
  4. Water quality monitor data reviewed and appropriate process changes made
  5. Auto shutdown
    • Pre-contact tank nitrate – High alarm trigger 47.8mg NO3/L (10.8mg N/L)
    • Review and adjust shutdown trigger level if appropriate
  6. Ability to flush to waste following site shutdown enabling unacceptable water to be disposed of
  7. Routine operational and regulatory water quality sampling of the raw and treated water to validate that the site is operating according to procedures. Any result detected outside of acceptable limits is recorded and published on a daily exception report and investigated
  8. Increase water quality sampling frequency in response to results detected outside of acceptable limits
  9. Operational borehole selection to enable isolation of individual boreholes
  10. Maintain site specific nitrate plan For the duration of notice
  11. Advise health authorities of any exceedances of the prescribed concentration value for nitrate.

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

  1. Complete detailed design and obtain permission (if required) for blending facilities for water from Sturminster Marshall/Shapwick water treatment works to include:
    Date: 31 May 2022
    • Washout improvements at Shapwick to enable each borehole to be washed out independently
    • A static mixer to enable the Shapwick/Sturminster flows to be blended in a controlled manner with the inflow from Black Lane
    • A pump on the outlet of Sturminster Marshall contact tank to enable the two sources to be blended through the static mixed.
    • Increased nitrate monitoring and control facilities
  2. Make operational and maintain thereafter blending facilities for water from Sturminster Marshall/ Shapwick water treatment works to ensure compliance with the nitrate standard.
    Date: 31 March 2024

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

  1. Define an audit strategy to determine whether the measures have been effective by the following means to include as a minimum:
    Date: 30 June 2022
    • Monitor raw and treated nitrate levels through compliance and operational sampling at an enhanced frequency (minimum twice weekly) for a minimum period of 12 months following completion of construction as specified in (b)1 and 2 above to monitor ongoing effectiveness
    • Validation of models used to calculate nitrate blend ratios
    • Review raw and treated nitrate monitor and sampling data to demonstrate effectiveness of the constructed blending facilities
    • Review annual catchment management reports
  2. Implement the audit strategy outlined in (c)1 until revocation of the notice
    Date: For the duration of notice

(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:
    • Provide a report regarding the audit strategy defined in (c)1
      Date: 30 June 2022
    • Submit improvement programme scope following completion of detailed design
      Date: 30 June 2022
    • Submit a report following completion of construction
      Date: 30 April 2024
  2. Review the risk assessment for Sturminster Marshall/ Shapwick works as required by Regulation 27(4) or 28(4) and subsequently submit a revised regulation 28 report.
    Date: 31 May 2024
  3. Submit a satisfactory completion report
    Date: 30 April 2025

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: WSX-2018-00002
Version 1.1