Notice of Regulation: Northumbrian Water – Tanks and Service Reservoirs

Notice Under Regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)

Northumbrian Water Limited: Tanks and Service Reservoirs

Reference: NES-2020-00011

Version Number: 4

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:
All service reservoirs, treatment works’ disinfection/ treated water tanks and break pressure tanks within the company’s operating area.

  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 on 21 October 2020, which states that there is or has been a significant risk of supplying water from Northumbrian Water Limited tanks and service reservoir assets that could constitute a potential danger to human health and could be wholesome.
  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 risks to drinking water quality and sufficiency

• Total Coliforms (Confirmed)

• E. coli (Confirmed)

• Clostridium Perfringens (Confirmed)

• Enterococci (Confirmed)

• Colony Counts at 22oC

• Residual Disinfectant – Total

• Residual Disinfectant – Free

To address the risk of ingress contamination and microbial growth.

  1. The Company are required to satisfy the following:


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

  1. Operate all service reservoirs and tanks in accordance with current company policy, standards and procedures aligning recognised standards of good practice.
    Date: Ongoing for the duration of this Notice
  2. Enhanced microbiological monitoring where service reservoir has not been inspected in accordance with the company’s policy. Including; where new risks to water quality from the asset are identified.
    Date: Ongoing for the duration of this Notice
  3. Complete frequent service reservoir and booster station maintenance check visits and escalate issues that present a water quality risk in accordance with company policy and procedures.
    Date: Ongoing for the duration of this Notice
  4. Proactive grounds maintenance on all service reservoir sites and at outflow discharge points.
    Date: Ongoing for the duration of this Notice
  5. Maintain records of remedial work completed on all cells.
    Date: Ongoing for the duration of this Notice
  6. Maintain contingency plans to protect human health in the event of a risk associated with drinking water quality, which should include liaison with local authorities and Public Health England.
    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. Develop a service reservoir and tanks asset health policy setting out expected company standards. This must include but not be limited to;
    Date: Complete
    • Inspection frequency (internal and external)
    • Flood testing methods
    • Age and construction type
    • Contamination from ingress
    • Contractors on site
    • Presence of microbial contaminants originating from upstream assets or treatment stages
    • Tank hydraulics
    • Turnover/ age of water
    • Pump failure on inlet
    • Pump failure on outlet
    • Telemetry information associated with cells
    • Sample line, tap and kiosk expectations
    • Hatch and air vent conditions
    • Recommissioning and returning to service
    • Ability to remove asset from supply for inspection and maintenance
    • Redundant assets or equipment not disconnected
    • Site maintenance- vegetation growth/ vermin control
    • Site security
    • Catchment risks
    • Review justification and operation of booster chlorination.
  2. Following completion of (b)1. ensure whole company is working consistently across all areas to new policy and expected standards. Implement revised training to water quality and operational teams to facilitate this policy update.
    Date: Complete
  3. Introduce methodology based on robust risk assessment tools to determine a risk-based inspection frequency of service reservoirs and tanks.
    Date: Complete
  4. Utilising methods developed in (b)3 complete an assessment of all company service reservoirs and tanks to create an asset health register which will support risk-based decisions on inspection.
    Date: Complete
  5. Confirm all service reservoirs and tanks that are over the company’s maximum inspection frequency standard and all tanks that are inoperable (cannot be removed from supply without enabling works).
    Date: Complete
  6. Following completion of (b)5. determine enabling work required to remove and inspect the inoperable service reservoirs and tanks. Refer to designated sites in Annex 1.
    Date: Complete
  7. Following completion of (b)6. produce an action plan of immediate and longer-term measures, to mitigate identified risks and complete necessary work to allow all service reservoirs and tanks covered by this Notice to be removed from supply for internal inspection and maintenance. This should be completed for all sites designated in Annex 1, and apply to the following risk-based categorisations:
    Date: Complete
    • Inoperable tanks – water treatment works
    • Inoperable tanks – network
    • In exceedance of inspection frequency standard – water treatment works
    • In exceedance of inspection frequency standard – networks
  8. Deliver the action plan produced in (b)7 for the designated sites in Annex 1, (allowing for any emergency, reactive changes in risk).
    Date: 31 March 2025 (date may be subject to change following (e) i.e. submission)
  9. Review all service reservoir and treated water tank site schematics and ensure drawings are up to date and include locations of regulatory sample taps, the outflow discharge points and all relevant valves.
    Date: 30 June 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 section (a) and (b).
    Date: 12 April 2021
  2. Implement, and keep under continuous review, the audit strategy defined in measure (c)1.
    Date: Following completion of measure (c)1. and for the duration of the Notice.

(d) not to supply water for regulation 4(1) purposes, 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 by 31 January and against the following milestones:
    Date: Annually by 31 January
    • a) Provide a copy of the audit strategy as produced under measure (c)1.
      Date: 10 May 2021 and updates where required
    • b) Service reservoir and asset health policy.
      Date: 31 October 2021
    • c) Methodology determining the risk based inspection frequency of service reservoirs and tanks.
      Date: Complete
    • d) List of all service reservoirs and tanks falling outside of inspection frequency standard or considered inoperable.
      Date: Complete
    • e) Report summarising the enabling work required to remove and inspect Annex 1 sites. Include the action plan of immediate and long term measures for mitigating risk and removal from supply ((b)7). Provide updated Annex 1 to include inspection dates for designated sites.
      Date: Complete
    • f) Annual progress report on the action plan delivery required under (b)8.
      Date: Annually by 31 January
    • g) For any Annex 1 sites where inspection and all remedial work has been completed under (b)8 in advance of 31 March 2025 submit evidence demonstrating completion with an accompanying Regulation 28(1) report for the site, submission to include an updated Annex 1 list for this Notice.
      Date: As required and by 31 April 2026
    • h) Following review of whole service reservoir and tank asset base, confirm all site schematics are up to date ((b)9)
      Date: 31 July 2022
  2. Submit a report in the event that any completed measure of this Notice needs to be altered in any way for any reason.
    Date: Ongoing for the duration of this Notice
  3. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with board level Director sign-off.
    Date: 30 April 2026 (date may be subject to change following (e)1.e. submission)

  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).

Nick Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
24 June 2022
Reference: NES-2020-00011

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