South West Water has been given the lowest possible environmental rating by the Environment Agency, classifying it as a "poor performing company" due to high levels of pollution. The company was downgraded from two stars to one star in the agency's annual Environmental Performance Assessment, marking the 15th consecutive year it has performed "significantly below target" for sewage pollution incidents.
The assessment grades England's nine water and sewerage companies primarily on their frequency of polluting rivers, streams, and coastal waters. For the 2025 assessment period, South West Water was among four companies receiving a one-star rating, indicating poor performance. Four other companies were rated as requiring improvement (two stars), while only Severn Trent Water achieved the highest rating of four stars.
Ofwat, the industry regulator, noted that South West Water met only seven of its 23 targets in 2025-26, with performance below target in most areas. The regulator specifically highlighted a substantial deterioration in performance regarding water supply interruptions. Despite an overall improvement in annual performance by 38%, the company's total pollution incidents remained more than double its target.
Customer satisfaction for South West Water also ranked poorly, placing 15th out of 17 in the sector. While performance related to storm overflows improved by 19%, it still fell short of the set target. However, the company was noted as the only one to have met its target for internal sewer flooding—wastewater entering properties—every year since 2020-21.
In response, a spokesperson for South West Water acknowledged the need for improvement under new management. "We know there's much more to do and although it will take time, we are taking action and making progress in the areas that matter most to our customers and the environment," the spokesperson said. The company stated it had reduced spills from storm overflows by 17% and spill duration by 25% in the past year, and insourced over 40 new leakage specialists. A multibillion-pound investment plan is underway to transform the network, improve water supply resilience, protect the environment, and tackle leaks.
Separately, a report from the Drinking Water Inspectorate, the Environment Agency, Natural Resources Wales, and Ofwat affirmed that South West Water's drinking water quality remains