South West Water Limited – AMP8 Secondary Chlorination

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

Reference: BRL-2023-00008

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): South West Water Limited, with registered number 02366665 (hereinafter called ‘the Company’).

Assets Affected:

The services reservoirs and water supply zones listed in Annex 1 of this notice.

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 15 June 2023, which states that there is or has been a significant risk of supplying water from the assets listed in Annex 1 of this Notice (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
Presence of Coliform Bacteria in WSZs (regrowth)	Coliform Bacteria	Multiple Hazard lines for example: Z406Hazard0007 and Z406Hazard0050
Presence of Coliform Bacteria in service reservoirs (regrowth)	Coliform Bacteria	Multiple Hazard lines for example: R156Hazard0002 and R156Hazard0103

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. Maintain statutory sampling as defined in the Regulations.
   Date: Ongoing for the duration of this Notice
2. Regular monitoring and review of the chlorine residual set point at the company’s water treatment works and secondary chlorination in the network to maintain chlorine residuals in the supply system.
   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. Undertake a hazard review of raw and treated water quality risks at all water treatment works to inform medium- and long-term water quality investment programme.
   Date: 31 March 2028
2. Install and commission secondary chlorination at the outlet of Pucklechurch SR.
   Date: 31 March 2026
3. Install and commission secondary chlorination at Marksbury PS and/or Clandown SR.
   Date: 31 December 2026
4. Complete a review of the need for secondary chlorination at the inlet to the South Bristol Ring Main and Banwell Riverside.
   Date: 31 December 2027
   • Dependant on the outcome of the review in (b)4., install and commission secondary chlorination at the inlet to the South Bristol Ring Main (transfer from Purton to Barrow NSSS Reservoir).
     Date: If required, by 31 December 2029
   • Dependant on the outcome of the review in (b)4, install and commission secondary chlorination at Banwell Riverside.
     Date: If required, by 31 October 2029
5. Install and commission chlorine monitoring at the following locations to improve the management of chlorine residuals in the network:
   • Blagdon East SR
   • Montpelier SR
   • Willsbridge PS
   • Beggar Bush SR
     Date: 31 March 2026

(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 August 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 Assets listed in Annex 1 of this Notice, 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. Confirm the completion of the hazard review, as described in (b)1.
   Date: 30 April 2028
3. Confirm completion of the installation and commissioning of secondary chlorination on the outlet of Pucklechurch SR.
   Date: 30 April 2026
4. Confirm completion of the installation and commissioning of secondary chlorination at Marksbury PS and/or Clandown SR.
   Date: 31 January 2027
5. Confirm completion of the review into the need for secondary chlorination at the inlet to the South Bristol Ring Main and Banwell Riverside as required by (b)4.
   Date: 31 January 2028
   • Dependant on the outcome of the review in (b)4, confirm the installation and commissioning of secondary chlorination at the inlet to the South Bristol Ring Main (transfer from Purton to Barrow NSSS Reservoir).
     Date: If required, by 31 January 2030
   • Dependant on the outcome of the review in (b)4, confirm the installation and commissioning of secondary chlorination at Banwell Riverside.
     Date: If required, by 30 November 2029
6. Confirm completion of the installation and commissioning of chlorine monitoring at the location in the network identified in (b)6.
   Date: 30 April 2026
7. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
   Date: 30 September 2024
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: 31 January 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
12 April 2024
Reference: BRL-2023-00008

Annex 1 – Assets Affected

Pucklechurch Service Reservoir outlet:

Asset	Hazard ID
R083 Knowle 1-OT	R083Hazard0002
R083 Knowle 1-OT	R083Hazard0003
R084 Knowle 2-OT	R084Hazard0002
R084 Knowle 2-OT	R084Hazard0001

Barrow SBRM inlet / Barrow NSSS Reservoir outlet:

Asset	Hazard ID
R050 Durdham Down-1-OT	R050Hazard0001
R050 Durdham Down-1-OT	R050Hazard0095
R205 Durdham Down Tr Outer-1A-OT	R205Hazard0001
R205 Durdham Down Tr Outer-1A-OT	R205Hazard0101
R206 Durdham Down Tr Inner-1B-OT	R206Hazard0001
R206 Durdham Down Tr Inner-1B-OT	R206Hazard0094
R155 Victoria 1A-OT north	R155Hazard0002
R155 Victoria 1A-OT north	R155Hazard0103
R156 Victoria 1B-OT south	R156Hazard0002
R156 Victoria 1B-OT south	R156Hazard0103

Banwell Riverside:

Asset	Hazard ID
R015 Bleadon 1-OT	R015Hazard0001
R015 Bleadon 1-OT	R015Hazard0092
R078 Hutton 1A-OT	R078Hazard0001
R078 Hutton 1A-OT	R078Hazard0101
R079 Hutton 1B-OT	R079Hazard0001
R079 Hutton 1B-OT	R079Hazard0093
R109 Montpelier 2-OT Compt 2	R109Hazard0001
R109 Montpelier 2-OT Compt 2	R109Hazard0107
R112 Oldmixton 1A-OT west	R112Hazard0001
R112 Oldmixton 1A-OT west	R112Hazard0091
R113 Oldmixton 1B-OT east	R113Hazard0001
R113 Oldmixton 1B-OT east	R113Hazard0091
R172 Weston Woods 1-OT	R172Hazard0001
R172 Weston Woods 1-OT	R172Hazard0092
R173 Weston Woods 2-OT	R173Hazard0001
R173 Weston Woods 2-OT	R173Hazard0092
R174 Weston Woods 3-OT	R174Hazard0001
R174 Weston Woods 3-OT	R174Hazard0092
R175 Weston Woods Tower 1-OT	R175Hazard0001
R175 Weston Woods Tower 1-OT	R175Hazard0092
R176 Worle 1A-OT west	R176Hazard0091
R176 Worle 1A-OT west	R176Hazard0234
R177 Worle 1B-OT east	R177Hazard0092
R177 Worle 1B-OT east	R177Hazard0236

Marksbury / Clandown:

Asset	Hazard ID
R027 Clandown 1A-OT East	R027Hazard0001
R027 Clandown 1A-OT East	R027Hazard0112
R028 Clandown 1B-OT West	R028Hazard0001
R028 Clandown 1B-OT West	R028Hazard0112
R148 Timsbury 2A-OT	R148Hazard0001
R148 Timsbury 2A-OT	R148Hazard0102
R149 Timsbury 2B-OT	R149Hazard0001
R149 Timsbury 2B-OT	R149Hazard0102
R181 Peasedown St.John 1A-OT W	R181Hazard0001
R181 Peasedown St.John 1A-OT W	R181Hazard0092
R182 Peasedown St.John 1B-OT E	R182Hazard0001
R182 Peasedown St.John 1B-OT E	R182Hazard0092
R194 Paulton 1A-OT north	R194Hazard0001
R194 Paulton 1A-OT north	R194Hazard0101
R195 Paulton 1B-OT south	R195Hazard0001
R195 Paulton 1B-OT south	R195Hazard0208