Table of Contents
South West Water has received the lowest possible environmental rating of one star from the Environment Agency, categorizing the firm as a “poor performing company” due to high pollution levels.
Environmental Performance Assessment
The regulator downgraded the company from two stars to one, noting it had performed “significantly below target” for sewage pollution incidents for the 15th consecutive year. The annual Environmental Performance Assessment evaluates England’s nine water and sewerage companies primarily on how frequently they pollute rivers, streams, and the sea.
For 2025, South West Water was one of four companies rated as poor performing, while four other companies received two stars for requiring improvement. Severn Trent Water stood out as the only company to attain the highest four-star rating.
Regulatory Findings and Performance
Industry regulator Ofwat stated that South West Water met only seven of its 23 targets in 2025-26, delivering below-target performance across most areas. The regulator highlighted that water supply interruptions “deteriorated substantially” and ranked the company 15 out of 17 in the sector for customer satisfaction.
Although annual pollution performance improved by 38%, the Environment Agency reported that total pollution incidents remained more than double the company’s target. Storm overflows performance saw a 19% improvement but still failed to meet its target. However, South West Water remained the only company to meet its target for internal sewer flooding every year since 2020-21.
Company Response
A spokesperson for South West Water stated that the company operates under new management with a renewed focus on performance enhancement. The spokesperson acknowledged that much work remains and explained that the firm is taking action in areas most important to customers and the environment.
The company noted it reduced spills from storm overflows by 17% over the previous year with spill duration down by 25%, and hired over 40 new in-house leakage specialists. These efforts are supported by record investments across the region as part of a multibillion-pound plan to improve long-term water supply resilience and protect the environment.
Drinking Water and Future Outlook
A separate report from the Drinking Water Inspectorate, the Environment Agency, Natural Resources Wales, and Ofwat confirmed that South West Water’s drinking water quality “remains exceptional, and consumers can be confident that their water is safe to drink.” The report also noted that internal sewer flooding performance, despite deteriorating, stays better than the industry average.
Nevertheless, regulators concluded that overall environmental performance is poor, with water supply interruptions remaining a significant concern making the firm one of the industry’s worst performers. To reverse these findings, the report stated the company must reduce interruptions, complete a transformation program targeting the root causes of failures, and substantially improve customer interactions and overall experience.
