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Northumbrian Water Limited – Stoneygate Service Reservoir

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

Reference: NES-2026-00002

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Northumbrian Water Limited, with registered number 02366703 (hereinafter called ‘the Company’).

Assets Affected:

  • R0700286 – Stoneygate SR 2 East

Details of this Notice:

  1. The Drinking Water Inspectorate (‘the Inspectorate’) has received a set of regulation 28(1) reports of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated 1 October 2020, which state that there is or has been a significant risk of supplying water from Stoneygate SR 2 East Service Reservoir 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:

Description of Risk

Hazard/ Hazardous Event/ Parameter

Hazard I D

Multiple hazard lines e.g.:

Inspection plan not met

E. coli

NNE_STO_R0700286_C002_HE194

Inspection plan not met

Total coliforms

NNE_STO_R0700286_C001_HE194

Inspection plan not met

Clostridium Perfringens (Confirmed)

NNE_ STO_R0700286_C004A_CFH

Inspection plan not met

Colony Counts at 22oC

NNE_ STO_R0700286_C007_CFH

Inspection plan not met

Residual Disinfectant – Total

NNE_ STO_R0700286_C010_CFH

Inspection plan not met

Residual Disinfectant – Free

NNE_ STO_R0700286_C009_CFH

Table 1: Table of the hazards, hazardous events, and/or parameters covered by this Notice, including the Hazard I D numbers and the description of risks.
  1. 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.

Requirements:

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

  1. Operate all tanks in accordance with current company policy, standards and procedures, that align to recognised standards of good practice.
    Date: Ongoing for the duration of this Notice
  2. Maintain proactive external site inspections, grounds maintenance, site security and asset maintenance. This must include periodic inspections of hatches, seals, redundant assets, sample taps, overflows, washouts, and air valves.
    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. Carry out an in supply full ROV inspection and robotic clean of the reservoir floor to define scope of work to be carried out during the outage.
    Date: 31 October 2026
  2. Define and develop a programme of works to facilitate an outage of Stoneygate Service Reservoir.
    Date: 30 November 2026
  3. Complete any enabling works required to isolate the reservoir. This includes:
    1. Installation of a replacement control valve and flow meter at Herrington to allow remote operation and adjustments to regulate flow and pressure during Stoneygate SR outages.
    2. Install a Pressure Reducing Valve (PRV) to supply Chapelgarth District Metered Area from RAS (Rainton to Stoneygate) strategic main to maintain supplies and reduce the risk of discoloration during Stoneygate SR outages.
    3. Install Stoneygate SR/RAS By-Pass Electrically Operated Valve (EOV) and Flow Meter which will assist the Doxford Park and Herrington control valves to maintain network pressure during peak demand periods.
    4. Installation of a replacement Bi-directional Flow Meter on the outlet of Stoneygate SR to accurately monitor and control flows into Sunderland to maintain supplies and reduce the risk of discoloration during Stoneygate SR outages.

Date: 31 July 2027

  1. Carry out a trial isolation of Stoneygate SR to confirm that the enabling works and supporting network can supply water to the area at all times to confirm full outage is possible.
    Date: 31 March 2028
  2. Complete the outage, inspection and any remedial works and return the tank to supply as specified under measure (b)2.
    Date: 31 December 2028

(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).
    Date: 31 July 2026
  2. 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 Stoneygate SR 2 East Reservoir, 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. Submit a report confirming the completion of an in supply full ROV inspection and robotic clean of the reservoir floor to define scope of work to be carried out during the outage, as specified in (b)1. Date: 30 November 2026
  3. Submit the programme of works required to facilitate an outage of Stoneygate Service Reservoir, as specified in (b)2. Date: 31 December 2026
  4. Submit a report confirming completion of all any enabling works required to isolate the reservoir, as specified in (b)3. Date: 31 August 2027
  5. Submit a report confirming completion of a trial isolation of Stoneygate SR to confirm that the enabling works and supporting network can supply water to the area at all times to confirm full outage is possible, as specified in (b)4. Date: 30 April 2028
  6. Confirm the isolation, inspection and remediation of the reservoir, as specified in (b)5.
    Date: 31 January 2029
  7. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 31 August 2026
  8. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  9. 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
  10. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 28 February 2030

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).

Signed

Nicholas Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
17 June 2026
Reference: NES-2026-00002

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