SEW accepts responsibility for foreseeable Tunbridge outages

(by Karma Loveday)

The Drinking Water Inspectorate (DWI) is to go beyond individual enforcement actions to work with South East Water (SEW) more systemically to improve water resilience for customers.

That news came as the DWI published the findings of its investigation into the November/December 2025 incident which left 24,000 customers in Tunbridge Wells off supply. The Inspectorate found the loss of supply and subsequent boil water notice were foreseeable and preventable. It said: “The event arose not from exceptional raw water conditions but from longstanding weaknesses in operational management, treatment optimisation, monitoring, maintenance and organisational preparedness at Pembury water treatment works. Taken together, the findings point to systemic and repeated failings across both operational control and emergency management arrangements, resulting in serious consumer impact.”

As a result, the DWI put the company into a ‘transformation programme’ under which it will work with SEW “to identify the root causes of poor performance and formalise these programmes into legal instruments, to deliver the changes needed to ensure consumers receive the reliable water supply they are entitled to expect”.

The publication coincided with an Environment, Food and Rural Affairs Committee hearing at which company and regulator leaders gave evidence. South East Water admitted it had failed customers and accepted the DWI position that the incident was foreseeable. This was in contrast to its previous evidence to the committee, which was based on its understanding of the situation at that time (January). SEW said its own internal investigation had subsequently drawn conclusions consistent with the DWI’s.

SEW chief executive David Hinton also told MPs of the actions the company is taking urgently to boost resilience; improve incident management and customer communications; and implement lessons learned. He has pre-emptively rejected any bonus he might have been awarded for the 2025/26 financial year, and the company has made £600,000 available to compensate businesses for income losses, on top of the Guaranteed Standards Scheme payments to which they are automatically entitled. 

Tunbridge Wells MP Mike Martin submitted evidence to the committee suggesting that the total losses for the 1,500 businesses affected by the incident could be around £18m. He has also proposed to Ofwat that the £22m fine it has consulted on levying on South East Water for historic outages (2020-23) would be better employed funding half the cost of a £44m investment plan for the Pembury works. Martin has designed this “resilience plan” with independent water experts.

In his evidence to the committee, Consumer Council for Water chief executive Mike Keil pressed home the legacy impact of the incident on customer trust. He said 54% in the affected area now keep bottled water at home in preparation for future incidents; 19% only drink bottled water; and 25% feel less comfortable using tap water for washing and teeth brushing.