Severn Trent's Compliance Risk Index, the measure regulators use to score drinking water quality failures, reached 10.32 in 2024. That was about 2.6 times its 2020 score of 3.94 and about five times the 2.00 deadband Ofwat set for the company.
A steady climb
The score did not jump in a single year. It stood at 5.65 in 2022, when Ofwat linked it to bacteriological failures at water treatment works, and 6.19 in 2023, before the rise to 10.32. In 2025 the Drinking Water Inspectorate made 69 recommendations to Severn Trent, the third-highest total in England after Thames Water and Dŵr Cymru Welsh Water.
Notices running to 2031
The Inspectorate's open program names the problems. At Frankley water treatment works, Severn Trent must install and commission an iron treatment solution by 31 May 2027. At Trimpley, a UV treatment design for Cryptosporidium is due by 31 March 2027, with commissioning by 31 March 2030. Further notices cover iron in seven water quality zones, with completion dates from January 2028 to October 2030, and PFAS at Cropston by 30 April 2030. Company-wide PFAS and lead strategies run to 30 April 2031.
Fewer customer contacts
Customer contacts have moved the other way. Contacts about water acceptability fell from 13,359 in 2017 to 7,996 in 2022, a drop of 40.1%. Ofwat has allowed £485 million for drinking water quality in 2025-30, within a total expenditure allowance of £15 billion.
How the drinking water program sits alongside drought, pollution and a regulator being redesigned, which institutions decide what, and where the 2025-30 investment is concentrated are set out in the full report. The full report, Water Systems Overview: Severn Trent, is available for USD 499 at https://ourfuturewaterintelligence.com/reports/water-systems-overview-severn-trent. For a free overview, read the Severn Trent Utility Snapshot at https://ourfuturewaterintelligence.com/utilities/severn-trent.