Severn Trent recorded 29 sewerage pollution incidents per 10,000 km of sewer in 2024, up from 21 in 2022, according to the Environment Agency. Ofwat's own figure for the year, 29.30, was well above the company's commitment of 19.50.
Top rating, rising incidents
The rise came while Severn Trent held the Environment Agency's top 4-star rating, which it kept in every year from 2019 to 2024. In 2024 the company recorded 274 sewerage pollution incidents against a green threshold of 191 or fewer, and the metric was rated amber. Serious incidents stayed low, at 1 in 2024.
Breaches settled without a fine
On 8 July 2026 Ofwat concluded its wastewater investigation into Severn Trent. The company accepted the breaches Ofwat found. Ofwat imposed no financial penalty and accepted forward-looking undertakings, and Severn Trent committed to invest £450 million by 2030 in a spills reduction program.
Spills are falling
Storm overflows tell a different story. Average spills per overflow were 25.4 in 2024, but Defra's December 2025 progress report recorded an average of 16 discharges in the September 2024 to August 2025 monitoring period, against a commitment of 20. The Environment Agency's full 2025 annual return, published in March 2026, puts the calendar 2025 average at 15.0 (calculated), against an England average of 20.5. Ofwat allowed £1,708.21 million for storm overflows in 2025-30 and set a target of 14 spills per overflow by 2029-30, alongside a 30% cut in pollution incidents.
What the undertakings mean for regulation under a single new water regulator, how the wastewater program compares with drinking water and drought pressures, and what to watch in 2027 are covered 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.