The Drinking Water Inspectorate (DWI) issued Severn Trent Water with a warning letter on Friday (20 June 2025), following the supply of water from Boughton Water Treatment Works in Chester with an abnormal change in taste and odour, with rejection of the water supply by consumers.
The company received forewarning of a taste and odour issue potentially associated to the works’ source water. According to the DWI, Severn Trent provided no evidence of a proactive risk assessment to limit potential consumer impact.
Onsite testing was ultimately initiated two weeks later and prior to the first consumer contact for an abnormal taste and odour. The DWI considers the company’s response inadequate in light of the forewarning received of a taste and odour issue potentially associated to the source water.
Severn Trent Water has taken actions to prevent a recurrence, including improved onsite odour testing of the source water.
Warning letters sent from the DWI are served as a warning to the company that any further repeat events of this nature could result in further sanctions, including enforcement or prosecution.
