Southern Water Services Limited – Ground Water Treatment Works HazRev Delayed Actions

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

Reference: SRN-2025-00008

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Southern Water Services Limited, with registered number 02366670 (hereinafter called ‘the Company’).

Assets Affected:

Asset Name	Reference
Angmering WSW	TS018
Balsdean WSW	TS036
Bottom Pond WSW	TK021
Bush Road Cuxton WSW	TK002
Calbourne WSW	TI005
Clapham WSW	TS019
Easton WSW	TH007
Falmer WSW	TS037
Findon Road WSW	TS021
Flemings WSW	TK024
Higham WSW	TK007
Ibthorpe WSW	TH013
Knighton WSW	TI009
London Road WSW	TK018
Lower Bush Cuxton WSW	TK039
Martin Mill WSW	TK027
Newmarket Lewes B WSW	TS044
Newmarket Lewes C WSW	TS039
Northfleet WSW	TK014
Overton WSW	TH016
Patching WSW	TS020
River Way Andover WSW	TH010
Rotherfield WSW	TS006
Selling WSW	TK041
Southover WSW	TS040
Sparrow Castle WSW	TK032
Stanhope Lodge WSW	TS022
Steyning WSW	TS008
Timsbury WSW	TH004
Twyford WSW	TH005

Table 1: List of assets affected and associated reference numbers

Details of this Notice:

1. The Drinking Water Inspectorate (‘the Inspectorate’) has received a regulation 28(1) report of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated 17 October 2019, which states that there is or has been a significant risk of supplying water from Ground Water Treatment Works (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
Pathogenic bacteria ingress route and failure of treatment process	E. coli	For example: 43790
Pathogenic bacteria ingress route and failure of treatment process	Enterococci	For example: 43791
Pathogenic Protozoa breakthrough presenting risk to public health	For Example: Cryptosporidium	For example: 43786
Increasing nitrate in source waters	Nitrate	For example: 43811
Insufficient water supply to downstream consumers	No Supply	For example: 43845, 43846, 43847
Failure of treatment poses risk to wholesomeness	Lead	For example: 43822
Failure of treatment poses risk to wholesomeness	Hydrocarbons e.g. PAH	For example: 43839
Discolouration in downstream network	For example: Manganese, Iron	For example: 43829, 43828
Failure of treatment poses risk to wholesomeness	Other chemical public health	For example: 43844
Compromised disinfection process	Turbidity	For example: 70083
Treatment by-products	Tetrachloromethane	For example: 43832
Failure of treatment poses risk to wholesomeness	Pesticides (e.g. Aldrin)	For example: 43806
Failure of treatment poses risk to wholesomeness	Taste	For example: 43837
Failure of treatment poses risk to wholesomeness	Odour	For example: 43838

Table 2: 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. Ensure all water quality related, scheduled operational and maintenance tasks are carried out at the current prescribed schedule.
   Date: Ongoing for the duration of this Notice
2. Ensure that any new risk identified is assessed in accordance with the drinking water safety plan methodology.
   Date: Ongoing for the duration of this Notice
3. Ensure that treatment works start-up protocols are followed when restarting each site.
   Date: Ongoing for the duration of this Notice
4. Ensure that the existing site-specific disinfection policies are annually reviewed and kept up to date with existing alarm and shutdown levels.
   Date: Ongoing for the duration of this Notice
5. Ensure the treatment works control and shutdown systems are operational and that all monitors are calibrated at the predefined frequencies.
   Date: Ongoing for the duration of this Notice
6. Continue to track borehole headworks condition and risk via the borehole headworks database and drinking water safety plan.
   Date: Ongoing for the duration of this Notice
7. Use site specific procedures where appropriate, including manual intervention or run to waste.
   Date: Ongoing for the duration of this Notice
8. Issue advice to consumers, where required, of improperly disinfected water.
   Date: Ongoing for the duration of this Notice
9. Provide bi-monthly updates at transformation meetings on progress of actions to include predicted float, actions completed to date and any major changes in delivery.
   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. Carry out mitigation of regulatory risk statements as identified in Appendices:
   a) Completion and commissioning of the actions in Appendix A– Phase 1 2026.
   Date: 30 June 2026
   b) Completion and commissioning of the actions in Appendix B – Phase 2 2026.
   Date: 31 December 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 2025
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 Groundwater treatment works, 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. Provide a report confirming completion and commissioning of all Phase 1 2026 actions.
   Date: 31 July 2026
3. Provide a report confirming completion and commissioning of all Phase 2 2026 actions.
   Date: 31 January 2027
4. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
   Date: 30 September 2025
5. Submit any revisions of the audit strategy produced under measure (c)2.
   Date: Within 1 month of a revision
6. 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
7. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
   Date: 31 January 2028

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

 Nick Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
31 July 2025
Reference: SRN-2025-00008 v1

Appendix A – Phase 1 2026

Unique ID	Site	Step Details	Complete and Commissioning Date
SW0017-1	Angmering WSW	Angmering WSW – UV bypass	31-Dec-25
SW0017-2	Angmering WSW	Angmering WSW – UV bypass	31-Dec-25
SE0153	Southover WSW	Southover WSW – PLC Replacement	04-Jan-26
KT0162-1	Sparrow Castle WSW	Sparrow Castle WSW – Headworks	04-Jan-26
SN0053	Rotherfield WSW	Rotherfield WSW – Obsolete PLC	31-Jan-26
SE0008	Balsdean WSW	Balsdean WSW Dead Legs	31-Jan-26
SE-Fal007	Falmer WSW	Falmer WSW – GAC deadleg	31-Jan-26
SN-STY-001	Steyning WSW	Steyning – Well 1, ingress risk	31-Jan-26
KM0027	Bottom Pond WSW	Bottom Pond WSW – Compliance sample tap	31-Jan-26
HS0054	Easton WSW	Easton WSW – BH1 panel	28-Feb-26
HS0054-b	Easton WSW	Easton WSW – Old Well and BH1 panel	28-Feb-26
SW_FIN001	Findon Road WSW	Findon Road WSW – Site PLC	28-Feb-26
KT0014	Fleming WSW	Fleming WSW – Run to waste	28-Feb-26
KT0014-1	Fleming WSW	Fleming WSW – Run to waste	28-Feb-26
KM0070	Higham WSW	Higham WSW – Obsolete chlorination system	28-Feb-26
KM-NOR001	Northfleet WSW	Northfleet WSW – Final sampling	31-Mar-26
HN0074	Overton WSW	Overton WSW – Borehole condition	31-Mar-26
SN0059	Steyning WSW	Steyning WSW – BH turbidity	31-Mar-26
KM-LBC003	Lower Bush Cuxton WSW	Lower Bush Cuxton WSW – Borehole Headworks conditions	31-May-26
IW0131	Calbourne WSW	Calbourne WSW – Well headworks condition	03-Jun-26
SW0040	Clapham WSW	Clapham WSW – run to waste	30-Jun-26
SE0088-1	Newmarket Lewes B WSW	Newmarket Lewes B WSW – Borehole B	30-Jun-26
SE0088-2	Newmarket Lewes B	Newmarket Lewes B – Borehole B	30-Jun-26
KM0127-1	Northfleet WSW	Northfleet WSW – (Chalk) Borehole 1	30-Jun-26
SW0064-2	Stanhope Lodge WSW	Stanhope Lodge WSW – Start-up turbidity	30-Jun-26
SW0064-3	Stanhope Lodge WSW	Stanhope Lodge WSW – Start-up turbidity	30-Jun-26
SN0051	Rotherfield WSW	Rotherfield WSW – Flooded chamber	30-Jun-26

 

Appendix B – Phase 2 2026

Unique ID	Site	Step Details	Complete and Commissioning Date
KT0162-2	Sparrow Castle WSW	Sparrow Castle WSW – Headworks	04-Jul-26
KM0299	Bush Road Cuxton WSW	Bush Road Cuxton WSW – BH sanitary seal	31-Jul-26
HN0025-3	Overton WSW	Overton WSW – Run to Waste	05-Aug-26
KM0043	Bush Road Cuxton WSW	Bush Road Cuxton WSW – No Run to Waste	05-Sep-26
SE0203	Newmarket Lewes C WSW	Newmarket Lewes C WSW – Ortho dosing	30-Sep-26
IW0167-1	Calbourne WSW	Calbourne WSW – On site hydrocarbons	30-Sep-26
HS0134	Easton WSW	Easton WSW – BH1 and BH2 tests	30-Sep-26
SW-PTG001-2	Patching WSW	Patching WSW – BH3 sanitary seal	30-Sep-26
KT0150	Selling WSW	Selling WSW – Run to Waste	30-Sep-26
KT0150-1	Selling WSW	Selling WSW – Run to Waste	30-Sep-26
SE0161	Southover WSW	Southover WSW – Lewes Valley Radio Network	30-Sep-26
HS0077	Twyford WSW	Twyford WSW – Well 1&2 new floor plates	30-Sep-26
SE0016c	Falmer WSW	Falmer WSW – GAC regeneration and return to service	30-Sep-26
SE0202-1	Newmarket C&D WSW	Newmarket C&D WSW – Newmarket C boreholes	30-Sep-26
SE0202-2	Newmarket C&D WSW	Newmarket C&D WSW – Newmarket C boreholes	30-Sep-26
HN0081	Ibthorpe WSW	Ibthorpe WSW – Contact main air release valves	30-Sep-26
HN0015-2	Ibthorpe WSW	Ibthorpe WSW – DO Constraint	30-Sep-26
KT0013-2	Flemings WSW	Flemings WSW – Contact main sediments	30-Sep-26
KT0013-3	Flemings WSW	Flemings WSW – Contact main sediments	30-Sep-26
HS0061	Timsbury WSW	Timsbury WSW- No Run- to- Waste	30-Sep-26
KM0127	Northfleet WSW	Northfleet WSW – (Chalk) Borehole 2	30-Sep-26
HS0056-3	Easton WSW	Easton WSW – Diesel tank bund	31-Oct-26
IW0123	Knighton WSW	Knighton WSW – Bisulphite tanks	31-Oct-26
KT0030-2	Martin Mill WSW	Martin Mill WSW – Weir Arrangement	31-Oct-26
KT0030-1	Martin Mill WSW	Martin Mill WSW – Weir Arrangement	31-Oct-26
KT0030-3	Martin Mills WSW	Martin Mills WSW – Contact Tank Bypass	31-Oct-26
KT-MaMi001	Martin Mill WSW	Martin Mill WSW – Contact Tank Bypass	31-Oct-26
KT0027	Martin Mill WSW	Martin Mill WSW – No Run to Waste	31-Oct-26
HN0001-1	River Way Andover WSW	River Way Andover WSW – GAC control and operation	30-Nov-26
HN0001-3	River Way Andover WSW	River Way Andover WSW – GAC control and operation	30-Nov-26
SENew014	Southover SWS	Southover SWS – Final RTW	30-Nov-26
IW0025	Calbourne WSW	Calbourne WSW – No raw run to water	22-Dec-26
KM0273	London Road WSW	London Road WSW – No run to waste	31-Dec-26
SE0155-1	Southover WSW	Southover WSW – Orthophosphoric acid deliver	31-Dec-26