South West Water, a subsidiary of Pennon Group, entered a guilty plea at Exeter Magistrates Court on 4 March 2026 following a prosecution brought by the Drinking Water Inspectorate (DWI). The case relates to a series of water quality failures that affected customers across Devon and Cornwall.

The DWI's prosecution centred on incidents in which water supplied to customers failed to meet the legal standards set out in the Water Supply (Water Quality) Regulations 2016. South West Water has been under sustained regulatory scrutiny since 2023 following a series of enforcement notices related to cryptosporidium contamination events in Brixham and other parts of Devon.

What happened

The Brixham cryptosporidium outbreak in May 2024 left thousands of customers without safe drinking water for several weeks and required a widespread bottled water distribution programme. The DWI subsequently issued improvement notices to South West Water covering treatment processes, monitoring frequency, and incident reporting.

The guilty plea on 4 March 2026 represents one of the most significant regulatory actions against a UK water company in recent years. Sentencing was adjourned pending a full facts hearing, with the penalty likely to include a substantial fine.

What this means for customers

Current customers in Devon and Cornwall are supplied water that meets legal standards. South West Water has invested in upgraded treatment at affected works since the 2024 outbreak. However, the prosecution highlights the importance of checking your specific supply zone's compliance record.

MyTapWater tracks all active DWI enforcement notices in real time. South West Water currently holds improvement notices related to treatment processes that are scheduled for completion by 2031.

What you can do

  • Enter your postcode above to check your specific supply zone's water quality data
  • If you are in a South West Water zone, review the PFAS and treatment status on your zone report
  • For the most current incident information, check South West Water's website and the DWI public register
  • Consider a certified water filter if you have concerns about PFAS — our guide recommends NSF/ANSI 58-certified reverse osmosis filters

Source: Drinking Water Inspectorate prosecution records; Exeter Magistrates Court listing; DWI annual report 2024.