- Drinking Water 2025 – Summary of the Chief Inspector’s report for drinking water in England
- Foreword
- Water supplies and testing
- Compliance with water quality standards
- Learning from microbiological failures
- Learning from turbidity failures
- Learning from chemical, taste and odour failures
- Learning from pesticide failures
- Asset health and service reservoir integrity
- Consumer contacts
- Drinking water quality events
- Water safety planning and risk assessment
- Perfluoroalkyl and polyfluoroalkyl substances (PFAS)
- Audit programme completed by the Inspectorate
- Air valve audits
- Enforcement, transformation and recommendations
- Materials in contact with drinking water (regulation 31)
- Security and Emergency Measures Direction - SEMD
- Network and Information Systems - NIS
- Research publications
- Whistleblowers
- Working with stakeholders
- Annex A – Number of tests carried out by companies
- Annex B – Compliance with standards
- Annex C – Compliance failures and events
Foreword
The provision of clean drinking water is fundamental to public health, social wellbeing and economic prosperity. Access to safe water is a basic human right recognised by the United Nations, and the water sector in England continues to provide drinking water of a very high standard. In 2025, public supplies complied with regulatory standards in 99.97% of tests, reflecting the strength of water safety planning, operational expertise and robust regulation. This high level of compliance should give consumers confidence, but it must not lead to complacency.
This report shows that the protection of drinking water depends on a multi-barrier approach from source to tap. Risks must be identified early, assessed properly and controlled before they affect consumers. Extensive regulatory sampling provides important verification, but sampling alone cannot protect supplies. Companies must maintain effective risk assessments, operate treatment processes within control, keep accurate data, and ensure that assets remain in a condition capable of protecting water quality. Where things go wrong, the Inspectorate investigates compliance failures and events, assesses the adequacy of company responses, and takes enforcement action where necessary to secure improvement and prevent recurrence.
Several themes run through the 2025 report. Asset health and resilience remain central, particularly the integrity of service reservoirs, treated water tanks, air valves and distribution mains. The report also highlights the importance of effective event management, including prevention, early detection, timely investigation, clear escalation and practical protection of consumers when supplies are affected. Treatment works must be managed with strong process control, reliable monitoring and appropriate management oversight, especially where multiple risks interact, such as turbidity, microbiology, disinfection by-products, taste and odour, and chemical removal. The report also demonstrates the importance of accurate data governance, because reporting errors and weak data systems can undermine confidence and misdirect regulatory effort even where water quality has not deteriorated.
The sector must also look ahead. Companies need to be more ambitious in reducing exposure to contaminants such as lead and in taking a precautionary approach to emerging risks including PFAS. Consumer acceptability, including discolouration, taste and odour, remains an important measure of public confidence and must be addressed through sustained operational control and investment. Following the Government’s Independent Review of the water system in England and Wales, the Inspectorate is working with fellow regulators to realign regulation so that it better addresses climate change, population growth, emerging risks, national security and long-term resilience. Systemic change is needed to support better planning, stronger accountability and investment decisions that protect consumers now and for future generations, while also protecting the environment and keeping bills affordable.
Dr Marcus Rink OBE
Chief Inspector of Drinking Water
