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Investigation into cause of Sussex loss of water supply published

An investigation into the reason why customers in areas of Sussex lost their water supply in May 2023 has now concluded. 

An investigation into the reason why customers in areas of Sussex lost their water supply in May 2023 has now concluded.  

Hardham Water Supply Works was automatically shut down late in the evening on Friday 12 May when sampling highlighted a change in water quality. None of this water entered public supply. 

Around 25,000 homes and businesses were affected at the peak of the incident, although supply was restored to 22,500 properties by Monday 15 May. All remaining customers’ supplies were restored a day later. 

Our extensive sampling processes look for 160 different substances in water, to ensure water quality is as high as it should be. 

Tim McMahon, Southern Water’s Water Director, said:  

“We are very sorry to those who were impacted by this disruption. We have carried out a thorough internal review into what happened, as it is vitally important we are transparent with customers when we fall short of expectations.   

“Our investigations found that the water entering Hardham from the nearby river and storage reservoir was unusual in that it contained more sediment and impurities than normal, which caused difficulties for our treatment processes.  

“Unfortunately, there is no way of knowing the exact source given the number of potential factors, such as agricultural and industrial run-off, but we have fully reviewed our own on-site policies and procedures so we are as prepared as we can be if this were to happen again.” 

A list of actions taken since the incident are included in the findings report

We have proposed a £63 million spend on improving the resilience of Hardham Water Supply Works after 2025, and are in discussions with regulators to make this happen as quickly as possible. 

We’re also reviewing where we can improve customer experience during water supply incidents and continue to address local water supply and demand challenges.  

Any customer who would like a paper copy of this report can contact us on papercopies@southernwater.co.uk.