After 15 Years of Sewage Pollution Below Target, South West Water Given Lowest Environmental Rating

Lowest environmental grade

The Environment Agency gave South West Water the lowest rating available in its annual Environmental Performance Assessment. The assessment grades England’s nine water and sewerage companies, with pollution of rivers, streams and the sea a major factor.

The agency said the company was significantly below its target for sewage pollution incidents for the 15th year running. Severn Trent Water was the only company to receive the top grade of four stars.

Targets and customer experience

Ofwat reported that South West Water achieved seven of its 23 targets in 2025-26, with results below target in most areas. Customer satisfaction remained a challenge, with the company placed 15th among 17 providers.

The company was the only one to meet its target for internal sewer flooding every year since 2020-21. That measure tracks how often wastewater enters people’s homes.

Pollution and drinking water

Pollution incidents included a treatment works discharge that killed thousands of fish in the St Austell River last year. Bathing at Exmouth was also discouraged following a pollution incident. A report by the Drinking Water Inspectorate, Environment Agency, Natural Resources Wales and Ofwat said drinking water quality remained exceptional and consumers could be confident it was safe.

Company and campaign response

A South West Water spokesperson said the company knew it had more work to do and was taking action, adding that progress would take time. The spokesperson also cited record investment across the region.

Campaigns head Jo Morley questioned the value of environmental ratings, asking why water company behaviour appeared to worsen year after year. Regulators said South West Water needed to reduce interruptions and complete a transformation programme addressing the causes of its failures, while improving customer interactions and experience.