Northumbrian Water Limited – Haz Rev Risks associated with Chlorate 

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

Reference: NES-2023-00006

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:

  • Assets listed in Annex 1

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 on 19 January 2024 which states that there is or has been a significant risk of supplying water from various water treatment works as listed in Annex 1 (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:

Description of Risk

Hazard/ Hazardous Event/ Parameter

Hazard I D

The risks associated with management of sodium hypochlorite, in particular temperature control, have been highlighted as a common theme through our HazRev process (NES-2021-00002). This notice brings all those risks together and ensures consistency to developing appropriate solutions. 

Chlorate (D101)

ESK_ABS_A001A_D101_CFH 

ESK_ABS_A004A_D101_CFH 

ESK_ABS_A004F_D101_CFH 

ESK_ABS_A005A_D101_CFH 

ESK_ABS_A030A_D101_CFH 

ESK_ABS_A040H_D101_CFH 

NNE_TRE_T0001706_D101_CFH 

NNE_TRE_T0004769_D101_CFH 

NNE_TRE_T0004807_D101_CFH 

NNE_TRE_T0015216_D101_CFH 

NNE_TRE_T0700335_D101_CFH 

NNE_TRE_T0021824_D101_CFH 

ESK_TRE_T009_D101_CFH 

NNE_TRE_T0700315_D101_CFH 

NNE_TRE_T0700318_D101_CFH 

NNE_TRE_T0700320_D101_CFH 

NNE_TRE_T0700324_D101_CFH 

NNE_TRE_T0700327_D101_CFH 

NNE_TRE_T0700330_D101_CFH 

NNE_TRE_T0700333_D101_CFH 

NNE_TRE_T0700335_D101_CFH 

NNE_TRE_T0700337_D101_CFH 

NNE_TRE_T0700338_D101_CFH 

NNE_TRE_T0700342_D101_CFH 

NNE_TRE_T0700346_D101_CFH 

NNE_TRE_T0700347_D101_CFH 

NNE_TRE_T0700351_D101_CFH 

NNE_DIS_Z0021431_D101_CFH 

NNE_DIS_Z0021433_D101_CFH 

NNE_DIS_Z0021434_D101_CFH 

NNE_DIS_Z0021435_D101_CFH 

NNE_DIS_Z0021451_D101_CFH 

NNE_DIS_Z0021461_D101_CFH 

NNE_DIS_Z0021463_D101_CFH 

NNE_DIS_Z0021466_D101_CFH 

NNE_DIS_Z0021471_D101_CFH 

NNE_DIS_Z0022221_D101_CFH 

NNE_DIS_Z0022222_D101_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. To ensure that wholesome water is always supplied to consumers, in accordance with the requirements of Regulation 28(4). 
    Date: Ongoing for the duration of this Notice
  2. Periodically review the water safety plan to ensure current control measures are in place and appropriate for the risk. 
    Date: Ongoing for the duration of this Notice
  3. Carry out a review of the chlorate monitoring strategy for all assets and their associated sampling points. 
    Date: Ongoing for the duration of this Notice
  4. Maintain water quality response procedures for investigation of chlorate trigger level contraventions as set out in the company procedures. 
    Date: Ongoing for the duration of this Notice
  5. Use suitable chemical products and ensure compliance with Regulation 31. 
    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 UK Health Security Agency (UKHSA). 
    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. Review and identify the most appropriate solutions to minimise risk of chlorate formation associated with management and storage of sodium hypochlorite at all water treatment work sites utilising sodium hypochlorite dosing for any of the following: raw water mussel control, primary disinfection, marginal chlorination, emergency disinfection or interstage metals oxidation.
    Date: 31 March 2026
  2. Design and develop the identified solutions for sites identified in measure b(1).
    Date: 31 March 2027
  3. Complete the construction, installation and commissioning of the chosen solutions, designed under measure (b)2. Commissioning must include the following to account for the changes made:
  • An appropriate maintenance regime for any installed processes;
  • Full integration of the new (or modified) processes into the site control and monitoring systems.
  • Updating of the Site-Specific Disinfection Policies and any associated site-specific procedures;
  • Updating of the Site Operating Manuals 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 installed (or modified) processes and the revised procedures, policies and manuals

Date: 31 March 2030

  1. Consider where the rationalisation and abandonment of secondary dosing systems can be applied at all the Network Secondary Chlorination Sites where sodium hypochlorite is used to modify network chlorine residual.
    Date: 31 March 2025
  2. Review and identify the most appropriate solutions to minimise risk of chlorate formation associated with management and storage of sodium hypochlorite at all the Network Secondary Chlorination Sites chosen for rationalisation in measure b(4).
    Date: 31 March 2026
  3. Design and develop the identified solutions for all sites identified in measure b(5). 
    Date: 31 March 2027
  4. Complete the construction, installation and commissioning of the chosen solutions, designed under measure (b)6. Commissioning must include the following to account for the changes made:
  • An appropriate maintenance regime for any installed processes;
  • Full integration of the new (or modified) processes into the site control and monitoring systems.
  • Updating of the Site-Specific Disinfection Policies and any associated site-specific procedures;
  • Updating of the Site Operating Manuals 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 installed (or modified) processes and the revised procedures, policies and manuals

Date: 31 March 2030

(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: 30 April 2024
  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 the various water treatment works as listed in Annex 1, 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 the appropriate solutions to minimise risk of chlorate formation associated with management and storage of sodium hypochlorite at all water treatment work sites utilising sodium hypochlorite dosing.
    Date: 30 April 2026
  3. Submit the designs for the solutions identified in measure b(1). 
    Date: 30 April 2027
  4. Submit a report confirming the completion of the construction, installation and commissioning of the chosen solutions identified in measure b(1).
    Date: 30 April 2030
  5. Submit a report detailing the Network Secondary Chlorination Sites chosen for rationalisation in measure b(4).
    Date: 30 April 2026
  6. Submit a report detailing the identified solutions for all sites identified in measure b(5). 
    Date: 30 April 2027
  7. Submit a report confirming the completion of the construction, installation and commissioning of the chosen solutions identified in measure b(5).
    Date: 30 April 2030
  8. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 31 May 2024
  9. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  10. 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
  11. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 31 May 2031

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
13 February 2024
Reference: NES-2023-00006

Annex 1

Asset Name 

Reference 

Chigwell Raw Water Tap Bullring Inlet 

A001A 

Chigwell 

T001 

River Stour (Lowlift) 

A004A 

Langham Raw Water Reservoir Outlet 

A004F 

Langham 

T004 

Abberton (Paterson weir) 

A005A 

Layer 

T005 

River Waveney Raw (Intake) 

A030A 

Barsham 

T030 

Ormesby Raw Water Reservoir Outlet 

A040H 

Ormesby 

T041 

Roding 

T009 

Barsham 

Z501 

Broome 

Z502 

Great Yarmouth 

Z504 

Lowestoft 

Z506 

Shadingfield 

Z508 

Gorleston 

Z514 

Barkingside 

Z601 

Billericay and Brentwood 

Z605 

Chelmsford Central 

Z607 

Chelmsford North 

Z608 

Chelmsford South and Margaretting 

Z609 

Dagenham 

Z610 

Dengie 

Z611 

Grays 

Z612 

Harold Hill 

Z613 

Hornchurch 

Z615 

Ilford 

Z616 

Langham 

Z617 

Layer 

Z618 

Ockendon and Stanford le Hope 

Z621 

Romford East 

Z624 

Romford West 

Z625 

Romford East 

Z625 

Seven Kings 

Z626 

Seven Kings 

Z632 

Thames 

Z633 

Upminster 

Z634 

Witham 

Z636 

Allenheads WTW 

T0700315 

Byrness Membrane Plant WTW 

T0700392 

Carrshields WTW 

T0700318 

Dalton WTW 

T0700320 

Fontburn WTW 

T0004769 

Fulwell WTW 

T0700324 

Gunnerton WTW 

T0700325 

Hawthorn WTW 

T0700327 

Honey Hill WTW 

T0001706 

Horsley WTW 

T0700330 

Lartington WTW – Barnard Castle Supply 

T0010145 

Lartington WTW – Bowes Supply (Chloraminated) 

T0014493 

Lartington WTW – Final Supply 

T0005166 

Lartington WTW – Mickleton Supply (Chloraminated) 

T0014974 

Lumley WTW 

T0700333 

Mosswood WTW – Durham Supply 

T0700335 

Mosswood WTW – Sunderland Supply 

T0021824 

Murton WTW – New Works 

T0700390 

New Winning WTW 

T0700337 

North Dalton WTW 

T0700338 

Otterburn Membrane Plant WTW 

T0700389 

Peterlee WTW 

T0700342 

Rochester Membrane Plant WTW 

T0700391 

Stonehaugh WTW 

T0700345 

Stoneygate WTW 

T0700346 

Thorpe WTW 

T0700347 

Tosson WTW 

T0004807 

Warkworth WTW – Northern Trunk Main Supply 

T0700388 

Warkworth WTW – Southern Trunk Main Supply 

T0700349 

Wear Valley WTW 

T0015216 

Whittle Dene WTW 

T0700351 

Wooler WTW – New Works 

T0700393 

N201 Fenham & Gosforth Park 

Z0021408 

N202 High Service North 

Z0021409 

N203 High Service South 

Z0021410 

N204 Fenham Booster 

Z0021411 

N206 Byker & Wallsend 

Z0021412 

N207 Low Service Gateshead 

Z0021413 

N208 Hillhead 

Z0021414 

N209 Wylam High Service 

Z0021415 

N210 Carr Hill 

Z0021416 

N211 Beacon Lough 

Z0021417 

N212 Whickham 

Z0021418 

N213 Birney Hill 

Z0021419 

N215 Heddon Whalton & Harlow Hill 

Z0021420 

N216 Low Service to City Centre 

Z0022218 

N217 Shotton 

Z0021422 

N219 Byrness 

Z0021423 

N220 Rochester 

Z0021424 

N221 Otterburn 

Z0021425 

N222 Peigh Hills & Amble 

Z0021426 

N224 Carrshield 

Z0021427 

N225 Allenheads 

Z0021428 

N226 Stonehaughshields 

Z0021429 

N229 Gunnerton 

Z0021431 

N230 Berwick 

Z0021432 

N231 Fowberry 

Z0021433 

N232 Warkworth 

Z0021434 

N234 Hexham Allendale & Blackhouse 

Z0021435 

N235 Hebron & Ashington 

Z0021436 

N237 Morpeth 

Z0021437 

N238 Fontburn 

Z0021438 

N239 Moorhouses 

Z0021439 

N240 Whitley Bay 

Z0021440 

N241 Thropton Rothbury & Longhorsley 

Z0021441 

N242 Whittington 

Z0021442 

N244 Netherwitton 

Z0021443 

N245 Birtley 

Z0022226 

S202 Downhill 

Z0021444 

S203 Fulwell 

Z0021445 

S204 Lumley 

Z0021446 

S205 Sunderland City Mayfair 

Z0021447 

S209 Stoneygate Outlet 

Z0021448 

S210 Wear Valley & Lumley 

Z0021449 

S211 New Winning & Peterlee 

Z0021450 

S213 Mill Hill Outlet 

Z0021451 

S214 Washington 

Z0021452 

S215 Marsden Cleadon & South Shields 

Z0021453 

S216 South Hylton Riverside 

Z0021454 

S217 Washington Fatfield to Herrington 

Z0022227 

S218 Thorpe to Easington Colliery 

Z0022228 

S219 Ryhope and Dalton 

Z0022229 

S220 Ryhope 

Z0022230 

T201 Lartington WTW to Longnewton 

Z0021455 

T203 Longnewton to Tees Ind Est 

Z0021457 

T204 Tees Ind Est to Redcar 

Z0021458 

T205 Longnewton Gravity 

Z0022219 

T206 Nunthorpe 

Z0021459 

T207 Stockton 

Z0021460 

T208 Redcar 

Z0021461 

T209 Sadberge 

Z0021462 

T210 Billingham 

Z0022220 

T211 Ormesby & Longbank 

Z0021463 

T214 Sedgefield & Aycliffe 

Z0021464 

T215 Mickleton 

Z0021465 

T216 Barnard Castle 

Z0022223 

T217 Bowes 

Z0022225 

W201 Honey Hill 

Z0021466 

W202 Honey Hill Castleside & Dyke Nook 

Z0021467 

W203 Oliver Burn 

Z0021468 

W205 Sacriston 

Z0021469 

W206 Derwent Trunk Main South & Durham 

Z0021470 

W207 Ferryhill Fishburn & Spennymoor 

Z0021471 

W208 Wear Valley 

Z0021472 

W211 Pelton 

Z0021473 

W212 Butterknowles & Staindrop 

Z0022221 

W213 Tunstall 

Z0022222 

W214 Blanchland 

Z0022231 

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