Water Systems Overview: Severn Trent

Executive overview

Key findings

£15 billion: Ofwat's total expenditure allowance for 2025-30, against £8 billion for 2020-25 (allowances)

4 stars: Environment Agency environmental performance rating in every year from 2019 to 2024; the only company rated 4 stars for 2024

10.32: Compliance Risk Index score for drinking water in 2024, against a deadband of 2.00 and up from 3.94 in 2020

£15.4 billion: regulatory asset base at 31 March 2026, up 13%, after £1,954 million of group capital investment in 2025-26 (utility statement)

Buyer relevance

Who the report is for

Engineering and treatment contractors

Use the Drinking Water Inspectorate notice table, from Frankley iron treatment by 31 May 2027 to Trimpley UV commissioning by 31 March 2030, to see which works need upgrades and when.

Water sector advisers and consultants

Use the institutional map and the July 2026 Ofwat enforcement outcome to see which decisions sit with Ofwat, the Environment Agency, the Inspectorate and Defra as the single regulator is designed.

Investors and credit analysts

Set the £15 billion totex allowance and £1,954 million of 2025-26 group capital investment against regulatory gearing of 63.6% and adjusted net debt of £9,647 million.

Water resource and drought planners

Compare distribution input, leakage and per capita consumption with the October 2026 drought levels in the North Staffs and Strategic Grid North zones.

Decision scope

Questions answered

How much can Severn Trent spend in 2025-30?

Ofwat's final determination allowed £15 billion of total expenditure for 2025-30, against £8 billion for 2020-25, with average household bills rising £185 before inflation by 2029-30.

How has drinking water compliance changed?

The Compliance Risk Index rose from 3.94 in 2020 to 10.32 in 2024, against a deadband of 2.00.

Is Severn Trent affected by the 2026 drought?

In the week of 9 to 15 October 2026 it was at drought level 2 in its North Staffs zone and not listed among companies with temporary use bans.

What did Ofwat's wastewater investigation find?

Ofwat concluded on 8 July 2026 that Severn Trent had breached its wastewater obligations, imposed no financial penalty and accepted undertakings; the company committed £450 million by 2030 to a spills reduction program.

How much is allowed for storm overflows?

Ofwat allowed £1,708.21 million for storm overflows, including monitoring, with a target of 14 spills per overflow by 2029-30.

Inside the report

Inside the complete report

Executive Overview

1. Water Resource Profile

2. Governance and Institutional Framework

3. Infrastructure and Service Delivery

Strategic Outlook and Opportunities

Source Register

Public preview

What to watch next

1. Water Resource Profile

Whether the Midlands leaves drought status over the winter of 2026-27 and how the Dove group refills; the first Ofwat assessment of 2025-26 leakage and per capita consumption against the PR24 path; any temporary use ban or drought permit; and progress on the Minworth scheme.

2. Governance and Institutional Framework

Publication of the Transition Plan and the water reform bill; Ofwat's 2025-26 performance report and category; delivery against the July 2026 undertakings and the £450 million spills program; and any rating action as gearing rises with the investment program.

3. Infrastructure and Service Delivery

The company's 2025 Compliance Risk Index score in Ofwat's next performance report; delivery dates on the Frankley (May 2027) and Trimpley (March 2027 design) notices; and pollution incident numbers for 2025.

Strategic Outlook and Opportunities

Half-year results for 2026-27 against the £2.2 billion to £2.5 billion investment guidance; the first Ofwat assessment of 2025-26 performance commitments; Ofwat decisions on PFAS and other notified items; and the PR29 framework once the Transition Plan sets the path to a single regulator.

Report page with tables of PR24 enhancement allowances for metering, sewage treatment growth and energy, 2025-30 targets for leakage, pollution and spills, and a delivery and finance table. — Sample page · page 10 of 13
The Strategic Outlook sets out Ofwat's 2025-30 allowances and targets, with capital investment, regulatory asset base, turnover and net debt for 2024-25 to 2026-27.

Included

What you receive

The complete PDF report: 13 pages, 6 sections, 15 tables and a register of 21 sources.

This edition

October 2026 edition.

Evidence & method

Evidence and method

The report draws on Ofwat's PR24 draft and final determinations, performance and financial resilience reports and enforcement decision, the Environment Agency's environmental performance, water resources and drought reports, and Drinking Water Inspectorate company data, annual report and improvement notices. Government reform documents, Severn Trent Water's 2025-26 accounts and Severn Trent Plc's 2025-26 results complete the picture.

Sources

21 sources, listed in the report's source register. Evidence current to 29 October 2026. Principal data periods: Regulatory years run April to March (2024-25 ended 31 March 2025). Ofwat performance reports 2021-22 to 2024-25; Environment Agency environmental performance data for calendar years 2017 to 2024; Drinking Water Inspectorate company data 2017 to 2022; the PR19 (2020-25) and PR24 (2025-30) price controls; Severn Trent Water Limited's accounts for the year ended 31 March 2026. Status checked against public sources on 29 October 2026. All currency is pounds sterling (£); Ofwat allowances are in the price base each document states..

Evidence boundaries

This report uses authoritative source material available at the stated research cutoff. It distinguishes published facts, calculated values and analytical interpretation. No independent modelling is performed. Forward-looking analysis reflects published plans, documented trends and stated uncertainties. It does not constitute legal, financial, investment or engineering advice.

Lead analyst

Robert C. Brears

Founder, Our Future Water Intelligence

Robert C. Brears is a water-security specialist and author whose work examines utility governance, infrastructure investment, climate resilience and long-term water-system change for executive and policy audiences.

Decision-focused utility intelligence
Published water-policy author
Evidence-grounded system analysis

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