South East Water Limited – Pembury Works Turbidity

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

Reference: SEW-2025-00041

Version Number: 2

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): South East Water Limited, with registered number 02679874 (hereinafter called ‘the company’).

Assets Affected:

• Pembury Treatment Works – T013
• Pembury – Y013

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 1 September 2025, which states that there is or has been a significant risk of supplying water from Pembury works (and associated assets as applicable) that could constitute a potential danger to human health or could be unwholesome.
2. The company in its communications to date has advised the Inspectorate that a microfiltration system was to be installed at Pembury Treatment Works. This action has not been completed prior to the lifting of the boil water notice therefore the Inspectorate has deemed it necessary to issue this Notice to ensure a permanent mitigation is put in place to prevent a recurrence.
3. 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
Failure of the treatment process	A002 Turbidity	T013-TREATMENT-A002

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.

4. 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. Optimise the existing treatment process at Pembury works.
   Date: Ongoing for the duration of this Notice.
2. Operate the treatment process at Pembury works in accordance with company policies and procedures.
   Date: Ongoing for the duration of this Notice.
3. Enhanced monitoring of raw, process and final water at Pembury works for microbiological and chemical parameters, as listed in schedule one of the Regulations, before and after the installation of the microfiltration process.
   Date: Ongoing for the duration of this Notice.
4. Investigate any sample result that breaches the Prescribed Concentration or Value (PCV), in accordance with company policies and procedures. Maintain appropriate contingency plans (including liaison with relevant stakeholders as appropriate) to protect human health.
   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. Complete the installation and commissioning of a microfiltration stage at Pembury Works.
   Date: Notify the Inspectorate immediately upon completion. No later than five calendar days from the serving of this notice: 5pm, 17 December 2025.
2. Define the operating parameters of the microfiltration plant at Pembury works.
   Date: Upon installation of the microfiltration plant in step (b)1.

(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). Sampling frequency for microbiological as defined in the regulations. For chemical parameters no less than once per week and for a minimum of one month.
   Date: Immediately, and ongoing for the duration of this notice. Submit the results of monitoring to the Inspectorate as soon as available.
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 Pembury 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 detailing the completion of installation and commissioning of microfiltration system at Pembury Treatment Works as required in step b(1).
   Date: No later than 5pm, 17 December 2025.
3. Report the parameters and operational data of the performance of the microfiltration plant, installed at Pembury works, as required in step b(2).
   Date: For two months minimum, after completion of step (b)1.
4. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
   Date: 17 December 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 March 2026.

Further Details of this Notice:

5. Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
6. 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.
7. 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 December 2025
Reference: SEW-2025-00041 v2