Wessex Water Services Limited – AMP8 PFAS Strategy

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

Reference: WSX-2023-00003 v4

Acceptance Notice:

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

1. Is satisfied that Wessex Water Services 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 31 August 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 14 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 the 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 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 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 that 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, design a proactive and systematic risk reduction strategy which shall include a prioritised mitigation methodology to progressively reduce PFAS concentrations in drinking water. Begin to implement mitigation measures on a risk basis for priority, over successive AMPS.
    Date: Ongoing for the duration of the undertaking and subsequent AMP periods.
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 Measures being delivered. Reports are 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 1b. above.
d. A summary of progress with the ongoing measures in the steps to be taken section.
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 above Tier 1 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 test 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 remedial measures taken as part of the PFAS strategy. Include as evidence for closure for this scheme, appropriate documentation to confirm that the actions set out in this Schedule of Work have been taken and that the company’s PFAS strategy is in place.
   Date: 30 April 2031

Further Details of this Acceptance Notice:

4. The Secretary of State is satisfied that Wessex Water Services 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)(b) 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

14 February 2025
Reference: WSX-2023-00003 v4

 

Annex A to Schedule for WSX-2023-00003 – Wessex Water Services Limited

Undertaking in respect of PFAS

Asset Name	Tier	Risk Assessment Reference (Name of Regulation 28 Report or Supply System Reference)	Supply System Name	Population of Zones Within Supply System
Arn Hill WTC	2 (WTC Tier 1)	RSKASMT-0000015539 H067 T15100630	Zone 28 Arn Hill	11,823
Barton Hill WTW	1	RSKASMT-0000003925 H067 T33011000	Zone 101 Shaftesbury	16,200
Bishops Cannings WTC	1	RSKASMT-0000007835 HO67 T15100632	Zone 38 Devizes Zone 39 Shepherds Shore	11,454 6,556
Black Lane WTC	1	RSKASMT-0000003543 H067 T33236000	Zone 89 Black Lane	19,321
Bourton WTC	1	RSKASMT-0000012119 H067 T15100610	Zone 38 Devizes Zone 39 Shepherds Shore Zone 40 Bourton	11,454 6,556 1,760
Brixton Deverill	1	RSKASMT-0000009462 H067 T15100635	Zone 121 Sutton Bingham Zone 124 Odcome Zone 139 Zeals	38,767 27,905 31,124
Castleton	1	RSKASMT-0000010230 H067 T67401000	Zone 77 Castleton	8,121
Charlton WTW	2	RSKASMT-0000013866 H067 T15100620	Zone 49 Allington Zone 51 Charlton	45,556 6735
Cherhill WTC	1	RSKASMT-0000013426 H067 T15100637	Zone 46 Cherhill	4,179
Clarendon Park WTC	1	RSKASMT-0000020489 H067 T33706000	Zone 113 Clarendon	16,961
Codford WTC	1	RSKASMT-0000002781 H067 T15101640	Zone 121 Sutton Bingham Zone 124 Odcome Zone 139 Zeals Zone 26 Heytsbury Zone 27 Chitterne	38,767 27,905 31,124 2,366 295
Corfe Mullen WTC	1	RSKASMT-0000014317 H067 T33101000	Zone 90 Purbeck Zone 95 Lytchett Matravers Zone 96 Poole Town Zone 98 Corfe Mullen	30,207 26,029 97,829 16,951
Dewlish WTC	1	RSKASMT-0000024033 H067 T33221000	Zone 87 Dewlish Direct	12,206
Dunkerton WTC	2	RSKASMT-0000005763 H067 T15100607	Zone 24 Dunkerton	7,904
Durleigh WTC	1	RSKASMT-0000031192 H067 T64021001	Zone 21 Danesborough	55,335
Durrington WTC	1	RSKASMT-0000020717 H067 T33766000	Zone 112 Newton Tony	20,207
Empool WTC	1	RSKASMT-0000018376 H067 T33416000	Zone 144 Dottery Zone 146 Charmouth Zone 66 Hooke Zone 78 Forston Zone 81 Weymouth Zone 83 Dorchester Zone 84 Empool Direct	8,294 1,348 10,227 6,377 54,940 22,466 11,489
Fulwood WTC	1	RSKASMT-0000011671 H067 T64051001	Zone 16 Fulwood	24,950
Littledown WTC	1	New site currently being commissioned. Risks in the process of being transferred. To be updated once available.	Zone 101 Shaftesbury Zone 139 Zeals Zone 89 Black Lane	16,200 31,124 19,180
Holt WTC	1	RSKASMT-0000024416 H067 T15100643 RSKASMT-0000024416 H067 T15101643 RSKASMT-0000024416 H067 T15102643	Zone 140 Trowbridge Zone 36 Holt Zone 41 Fiveways Zone 60 Batheaston	29,904 11,056 34,509 23,116
Hooke WTC	1	RSKASMT-0000015398 H067 T33511000	Zone 66 Hooke	10,227
Ivyfields WTC	1	RSKASMT-0000016510 H067 T15100624	Zone 37 Bowden Zone 38 Devizes Zone 41 Fiveways Zone 60 Batheaston	26,575 11,454 34,509 23,116
Laycock WTC	1	RSKASMT-0000003004 H067 T15100645	Zone 37 Bowden Zone 38 Devizes	26,575 11,454
Maiden Newton WTC	1	RSKASMT-0000018395 H067 T33641000	Zone 70 Maiden Newton	1,631
Maundown WTC	1	RSKASMT-0000011827 H067 T64041001 RSKASMT-0000011827 H067 T64041002	Zone 10 Maundown Central Zone 117 Chard Town Zone 121 Sutton Bingham Zone 122 Stocklinch Zone 124 Odcome Zone 10 Maundown East Zone 2 Maundown North	89,328 14,187 38,767 7,129 27,905 52647 40090
Mere WTC	1	RSKASMT-0000021018 H067 T33061000	Zone 103 Mere Zone 121 Sutton Bingham Zone 124 Odcome Zone 139 Zeals	17,297 38,767 27,905 31,124
Middle Barn Farm WTC	1	RSKASMT-0000012227 H067 T33716100	Zone 114 Salisbury	50,277
Milborne St Andrew WTC	1	RSKASMT-0000016116 H067 T33206000	Zone 84 Empool Zone 88 Milborne St Andrew Zone 90 Purbeck	11,489 2,165 30,207
Milbourne WTC	1	RSKASMT-000009397 H067 T15100647	Zone 49 Allington Zone 52 Milbourne	45,556 8,485
Portesham/Friar Waddon WTC		RSKASMT-000004115 H067 T33631500	Zone 80 Portesham	1,302
Rodbourne WTC	2	RSKASMT-000003437 H067 T15100650	Zone 38 Devizes Zone 41 Fiveways Zone 49 Allington Zone 60 Batheaston	11,454 34,509 45,556 23,116
Shepherds Shore WTC	2	RSKASMT-0000016092 H067 T15102651	Zone 39 Shepherds Shore	6,556
Sturminster Marshall WTC	1	RSKASMT-0000016131 H067 T33126200	Zone 92 Shapwich Zone 95 Lytchett Matravers Zone 98 Corfe Mullen	2,330 25,538 16,930
Sutton Bingham WTC	1	RSKASMT-0000020749 H067 T67021001	Zone 121 Sutton Bingham Zone 124 Odcome	38,767 27,905
Tatworth WTC	1	RSKASMT-0000022237 H067 T67351000	Zone 118 Tatworth	3,150
Tucking Mill WTC	3 (WTC Tier 2)	RSKASMT-0000020380 H067 T15100652	Zone 58 Tucking Mill Zone 59 Hampton Down	1,942 29,772
Upton Scudamore WTC	2	RSKASMT-0000023081 H067 T15100664	Zone 140 Trowbridge Zone 30 Upton Scudamore Zone 55 Newton Meadows	29,904 64,900 10,792
Washpool WTC	2	RSKASMT-0000020046 H067 T15100612	Zone 61 Monkswood	42,785
Yatesbury WTC		RSKASMT-0000023641 H067 T15100657	Zone 47 Yatesbury	690