South East Water Under Fire For Supply Failure

On 4 December 2025, South East Water issued a boil water notice to business and household customers for Tunbridge Wells and the surrounding area. This was due to water quality challenges identified in its water treatment works in Pembury.

However, a Guardian investigation revealed that the same plant responsible for this supply failure was issued with a notice from the Drinking Water Inspectorate highlighting the potential for harm to human health from water supplied by the Pembury site. 

This has put the struggling water supplier under even more pressure, given that it will need to provide compensation to all of those affected by the ten-day boil water notice in December. 

What happened to the Tunbridge Wells water supply? 

The final disinfection process at the Pembury water treatment site could not be guaranteed to have worked, according to South East Water. Initially, the firm shut down water supplies leaving the site in the hope of fixing the problem within a day or two of identifying it.

However, by 3 December it recognised that the issue was more challenging and would take longer to remedy. This led to South East Water restoring the connection to the Pembury plant, but with the boil water instruction for all homes and businesses in the area. 

It affected some 24,000 customers who were instructed to use the water supply only for flushing toilets or showering, while ensuring that they boiled their water and then let it cool if they wanted to drink it or use it for cooking. 

The boil water notice has since been lifted and normal service has resumed for those in Tunbridge Wells and the surrounding area. 

Why did people need to boil their tap water?

Boiling the water coming from taps was a precautionary measure to ensure it was safe for human consumption and use. 

This is because there was a concern about potential contamination from pesticides, as well as bacteria including E. coli, Enterococci and Clostridium. Boiling the water kills these bacteria, which makes the water safe to drink. 

However, South East Water also delivered bottled water to thousands of homes and businesses in the area while the boil water notice was in place. 

Will those affected receive compensation for the incident?

Yes, both business and residential customers who were affected by the boil water notice will receive compensation from South East Water. 

This will automatically be applied to accounts in the case of household customers. For business water customers, the compensation will be sent to the relevant business water retailer, who will then apply it to the accounts of affected customers. 

The process for business water customers is different, because businesses can compare business water suppliers and switch to alternative retailers if they choose, whereas residential customers do not have this option. 

What does South East Water have to do now?

Aside from providing compensation to those affected, South East Water needs to continue with its work to improve the infrastructure that serves Tunbridge Wells and other parts of Kent. 

The Drinking Water Inspectorate notice from September 2024 set out a range of measures that the organisation needs to take to reduce the risk of water quality falling in the region, some of which have yet to be completed. 

For instance, in the 2024 notice, South East Water needs to desludge its sludge lagoons by 31 January 2026 and it needs to “complete maintenance work on the springs network” by 30 September 2028. 

There are a host of other activities the company needs to undertake too, including upgrading its granular activated carbon (GAC) system for water treatment and increasing the capacity of its settlement tank. 

Have other water suppliers had similar issues?

It’s rare for water suppliers to issue boil water notices, but a similar incident occurred in Devon in 2024. An outbreak of cryptosporidium in Brixham led to South West Water issuing a boil water notice when part of its supply was found to contain the parasite. 

In this case, the parasite was detected after testing due to several people falling ill as a result of cryptosporidium in May. Within two days of beginning the testing process, cryptosporidium was detected in the Hillhead area and the boil water notice was issued. 

This highlights the importance of investment in the UK’s water infrastructure and improved testing throughout the network to ensure tap water remains safe and any issues or contamination are promptly identified. 

If you have been affected by this kind of issue, it’s important to speak to your business water retailer to find out how they will pass on the compensation you are due from the relevant water supplier.