Full Breakdown
Potentially Illegal Sewage Discharges in England’s Waterways
7/23/2026, 11:19:35 AM
Core Findings on Potentially Illegal Sewage Discharges
Professor Peter Hammond, a retired academic who has campaigned on sewage-spill issues, obtained secret court documents that define “heavy rain” for regulatory purposes. Using that definition, he examined spill records from more than 350 storm-overflow outlets covering all nine English water companies. He concluded that roughly 86 % of raw-sewage discharge hours occurred when rainfall was not classified as “heavy,” meaning the releases may have breached UK law that prohibits raw sewage discharge in “normal” weather.
Legal Framework and Recent Oversight Findings
UK legislation requires that raw sewage not be released except under “exceptional circumstances,” typically interpreted as heavy rainfall that overwhelms treatment capacity. The Environment Agency (EA) has not previously clarified the exact rainfall threshold, allowing water companies to argue that many discharges were lawful. In 2024 the Office for Environmental Protection (OEP) ruled that the EA was not applying the legislation correctly, stating that the agency was permitting spills in “normal” weather rather than only in “exceptional circumstances.” Following the OEP report, the EA issued new guidance last year urging that spills should not occur during normal weather, though it has not confirmed a strict “exceptional circumstances” rule.
Scope of the Analysis and Key Statistics
Hammond’s review covered the largest treatment works and a representative sample of smaller sites across England, serving over 30 million people. His analysis showed:
- About 86 % of raw-sewage spill hours happened without heavy rain.
- Every water company examined had a potential illegality rate exceeding 70 % for the past two years.
Regional variations in rainfall thresholds were tested and did not materially alter these percentages, as most spills occurred during relatively low rain levels.
Official Responses from Regulators and Industry
The EA acknowledged that its “heavy rain” definition applied only to Southern Water sites and that rainfall thresholds differ regionally. An EA spokesperson said enforcement must consider site-specific permits, rainfall totals, and other factors, and that the agency would “always take action” if a breach is proven, though it could not disclose ongoing legal proceedings.
Water UK, representing the water companies, cited the High Court and OEP rulings, stating that discharges should occur only in “exceptional circumstances” or when preventing them would be technically possible but excessively costly. The group added that it aims to eliminate all discharges as quickly as physically feasible.
Verbatim Quotes
- “It's totally outrageous, both from the point of the water companies who are exploiting the weak regulation but also from the Environment Agency's point of view, where they've not been doing their job properly,” — Prof Hammond
