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.

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.

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:

4. Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
5. 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.
6. 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