South West Water Limited – AMP8 PFAS Strategy

Water Industry Act 1991 (as amended) (“the Act”): Section 19(1)(b)

Reference: SWB-2023-00014 v4

Acceptance Notice:

The Drinking Water Inspectorate, on behalf of the Secretary of State for Environment, Food, and Rural Affairs:

1. Is satisfied that South West Water Limited “the Company” in supplying water from all water supply systems (raw water assets, water treatment works and treated water assets), which are for the time being listed in the Annex to this Schedule of Works which may be at risk of breaching the wholesomeness and no deterioration standards due to PFAS concentrations. This means that the Company is likely to contravene its duties under Sections 68(1)(a) and 68(1)(b) of the Act and the requirement set in regulation 4(2)(b) of the Water Supply (Water Quality) Regulations 2016 (as amended) (“the Regulations”).
2. Has notified the Company on 22 November 2023 that the Secretary of State is considering making in relation to the company an enforcement order under Section 18 of the Act.
3. Notes that the Company has on 24 June 2024 given a new undertaking under Section 19 (1) (b) of the Act, to take the following steps by the dates shown.

Steps to be taken:

1. Ensure that PFAS have been assessed as a hazard, as part of the regulation 27 Risk Assessment for the supply systems listed in the Annex to this Schedule, according to a Drinking Water Safety Plan approach and the Inspectorate’s latest guidance on the risk assessment of individual and total PFAS. Ensure that regulation 28 documents are reviewed (at least annually) and updates provided as necessary.
   Date: Ongoing for the duration of the undertaking
2. Keep under review the company’s strategy for the protection of public health and for compliance with drinking water quality standards with respect to PFAS.
   Date: Ongoing for the duration of the undertaking
3. Conduct surveillance, including sampling and analysis for PFAS in line with the Inspectorate’s latest published guidance on PFAS.
   Date: Ongoing for the duration of the undertaking
4. Where there are new PFAS detections, or a change in detected levels, conduct operational monitoring; sampling (and analysis) extended upstream of abstraction points into catchments and sub-catchments, and downstream through different stages of water treatment to the final water sampling location, to identify the source, concentration and fate of PFAS compounds.
   Date: Ongoing for the duration of the undertaking
5. Following on from step 4, continue to conduct risk-based, enhanced, investigatory sampling (and analysis), where PFAS are detected.
   Date: Ongoing for the duration of the undertaking
6. Undertake catchment characterisation and identification of PFAS sources (minimum requirements defined in DWI guidance), for example, product usage (existing data available and data gathering), catchment modelling with analysis of weather, surface and groundwater flows, catchment walkovers, identification of high-risk locations.
   Date: Ongoing for the duration of the undertaking
7. Initiate and maintain regular engagement with relevant stakeholders, to ensure that catchment risk assessments are current.
   Date: Ongoing for the duration of the undertaking
8. Participate in relevant research and development activities.
   Date: Ongoing for the duration of the undertaking
9. Where PFAS are detected at concentrations at or above tier 1 values in a single final water (or downstream treated water) sample, or two or more raw water (water sampled from any point prior to the final treated water point at the water treatment works) samples in a supply system not currently listed in the annex to this undertaking, submit a change request to the Inspectorate to add the supply system to the annex, unless a mitigation plan has already been developed for this supply system.
   Date: Ongoing for the duration of the undertaking
10. Maintain and continually review the company’s PFAS strategy.
    Date: Ongoing for the duration of the undertaking
11. For all sources that fall into tier 3, design, develop and implement mitigation to reduce PFAS concentrations in drinking water to at least tier 1 concentrations, with a high priority.
    Date: Ongoing for the duration of the undertaking
12. For all sources that fall into tier 2, companies should design a proactive and systematic risk reduction strategy implementing a prioritised mitigation methodology to progressively reduce PFAS concentrations in drinking water.
    Date: Ongoing for the duration of the undertaking
13. For all sources that fall into tier 1, design a basic mitigation plan, which can be implemented should concentrations increase, or toxicological or other information change that requires mitigation be delivered.
    Date: 31 March 2030

Reporting:

1. At regular intervals provide the Inspectorate with reports on progress made with carrying out the steps set out in the Action Plan. Reports to include at least the following details:

a) All sampling and analysis data from the monitoring of raw and treated water in the supply systems named in the annex.
b) Details of the remedial steps that comprise the programme of work including commencement and completion dates for investigations, design, tendering, construction, and commissioning.
c) Current state of progress with the steps referred to in 1(d)b) above.
d) A summary of progress with the ongoing measures in section 1(c).
e) A statement of implications of any slippage of the programme and details of activities planned to bring programme back on target.
f) Whether the company has any other reason to believe it may not be able to meet any of the key dates set out in this Schedule of Work.
g) The latest version of the company’s PFAS strategy.
h) Evidence of no PFAS detections in the final water, with mitigations in place over Tier 1 levels in a supply system for one year and evidence of the mitigation plan, in order to remove the supply system from the undertaking annex.
Date: Annually for the duration of the Undertaking. Reporting periods are Jan-Dec. Reports to be submitted by 31 January each year that the Undertaking is in place.

2. Continue to monitor at an enhanced frequency for PFAS for a period of 12 months following commissioning of any work associated with the Action Plan to demonstrate the effectiveness of the remedial measures taken. Date: 31 March 2031

3. Provide a final report to the Inspectorate on the efficacy of the steps taken as part of this undertaking. Include, as evidence of closure for this scheme, appropriate documentation to confirm that the actions set out in this Schedule of Work have been completed satisfactorily.
   Date: 30 April 2031

Further Details of this Acceptance Notice:

4. The Secretary of State is satisfied that South West Water Limited has given and is complying with an undertaking to take all such steps as appear to the Secretary of State for the time being to be appropriate to secure or facilitate compliance with the requirement of regulation 4(2)(c) of the Water Supply (Water Quality) Regulations 2016 (as amended).

Authorised by the Secretary of State to sign in that behalf

Nicholas Adjei
Deputy Chief Inspector, Drinking Water Inspectorate
21 March 2025
Reference: SWB-2023-00014 v4

Annex A to Schedule for SWB-2023-00014 v4

South West, Bournemouth and Isles of Scilly

Undertaking in Respect of PFAS Supply System Name	Population of zones within system	Risk Assessment Reference (Name of regulation 28 Report for Supply System Reference)
Plump WTW	44	205522
Tommys WTW	44	205529
Higher Town WTW	49	205536
Middle Town WTW	49	205537
Lower Town WTW	49	205538
Vane Hill WTW North/South	116	205597, 205586
Great Pool WTW	89	205566
Porthelick WTW	1643	205556
College WTW	36530	205257
Drift WTW	41555	205009
Stithians WTW	38005	205255
Wendron Final	33719	205254
De Lank WTW	38022	205253
Lowermoor WTW	18294	205008
Restormel WTW	194109	205007
Bratton Fleming WTW	24456	205252
Horedown WTW	16721	205251
Prewley WTW	68621	205005
Tamar WTW	32269	205250
Bastreet WTW	19615	205249
Mayflower WTW	166332	205376
Dousland WTW	160581	205248
St Cleer WTW	89213	205247
Avon WTW	73048	205002, 205246
Burrows WTW	55973	205015
Littlehempston WTW	154555	205244
Tottiford WTW	111232	205001
Venford WTW	73048	205243
Allers WTW	59075	204999
Dotton WTW	106743	205256
Greatwell WTW	32160	204997
Hook WTW	32160	205273
Kersbrook WTW	56197	204996
Pynes WTW	169940	205288
Wilmington Final	41555	205274
Alderney WTW	243248	205664
Knapp Mill WTW	148708	204994
Stanbridge WTW	38005	205301
Woodgreen Final	34659	205300

Bristol Water

Undertaking in Respect of PFAS Supply System Name	Population of zones within system	Risk Assessment Reference (Name of regulation 28 Report for Supply System Reference)
Oldford TW	57396	T19Hazard0430; T19Hazard0427
Frome TW	57396	T11Hazard0424
Chelvey TW	57486	T08Hazard0505
Alderley TW	20779	T01Hazard0341
Barrow TW	485425	T05Hazard1639
Cheddar TW	156743	T07Hazard0731
Clevedon TW	16272	T08Hazard0538
Purton TW	852921	T21Hazard2428
Littleton TW	280567	T17Hazard2002
Tetbury TW	7700	T26Hazard0423
Banwell TW	167164	T04Hazard1117
Forum TW	38430	T12Hazard0375
Stowey TW	325924	T25Hazard1214
Shipton Moyne TW	50005	T24Hazard0461