Thames Water Utilities Limited – North Cotswolds Supply System Lead

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

Reference: TMS-2025-00002

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Thames Water Utilities Limited, with registered number 02366661 (hereinafter called ‘the company’).

Assets Affected:

• T07U.705 Seven Springs works
• RSR7097 Upper Slaughter A
• RSR7098 Upper Slaughter B
• YTMS1181 – Cirencester Supply System
• YTMS1212 – North Cotswolds Supply System

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 21 February 2025, which states that there is or has been a significant risk of supplying water from North Cotswolds Supply System (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
Contamination of the water supply	Lead	TMS-7-Z0302-MDCT164-Z0302-B007B

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. Ensure that the lead parameter has been assessed as a hazard as part of the regulation 27 risk assessment for the North Cotswolds Supply System that includes the water supply zones, according to a Drinking Water Safety Plan approach. Ensure that regulation 28 documents are reviewed, and updates provided as necessary.
   Date: Ongoing for the duration of this Notice.
2. Maintain contingency plans for the protection of public health associated with drinking water quality, to include liaison with Local Authorities and the United Kingdom Health Security Agency (UKHSA).
   Date: Ongoing for the duration of this Notice.
3. Water Quality response procedures in place for investigation of contraventions including process optimisation and reporting, consumer complaints and event response.
   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 a review of the control philosophy for the lead parameter in the North Cotswolds Supply System, with a view to reducing the risk of a breach of the prescribed regulatory concentration of lead.
   Date: 31 January 2026.
2. Carry out an assessment of properties within the Bourton Water Supply Zone, to fully ascertain the risk of lead in the zone. The assessment shall include capturing the age of a range of properties located within the zone and the pipe material composition to those properties.
   Date: 31 January 2026.
3. Based on the outcome of measure (b)2, complete remedial works where necessary, to reduce the risk of lead compliance breaches within the zone.
   Date: 31 December 2028.
4. Based on the outcome of measure b(2) and b(3), ensure the level of ortho-phosphate within the zone is clearly defined and sufficient for the risk posed.
   Date: 31 March 2029.

(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 September 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 the North Cotswolds Supply System, 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 the outcome of the review carried out in measure (b)1.
   Date: 28 February 2026.
3. Provide the outcome of the assessment implemented in measure (b)2.
   Date: 28 February 2026.
4. Provide evidence to confirm remedial works have been implemented, as required by measure (b)3.
   Date: 31 January 2029.
5. Provide evidence to confirm that the level of orth-phosphate is clearly defined and sufficient, as required by measure (b)4.
   Date: 30 April 2029.
6. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
   Date: 31 October 2025.
7. Submit any revisions of the audit strategy produced under measure (c)2.
   Date: Within 1 month of a revision.
8. 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.
9. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
   Date: 30 April 2030.

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
15 July 2025
Reference: TMS-2025-00002 v1