Proposed Reforms - What is likely to change?
- a new hazard classification (used to group reservoirs by how likely they are to cause harm if there is a failure)
- a framework for a safety management system, which incorporates current safety management practices with additional good practice from other high-risk sectors
- a cost-benefit analysis of the proposed approach – this will be used to inform development of the new legislation (it is not about costs and benefits for individual reservoirs or their owners)
- hazard potential (based on dam height and reservoir volume),
- risk to life (based on average societal loss of life) and
- property damages.
- Part 1- Introduction to the hazard classification research(External link)
- Part 2 - Evidence gathered about safety management in other countries and sectors(External link)
- Part 3 - Developing the new hazard classification system(External link)
- reduced risk to life
- reduced risk of damage to property, infrastructure and the environment
- reduced risk of economic disruption
- fair and proportionate regulation of reservoir safety
- New primary legislation to replace the Reservoirs Act 1975;
- Retaining the Act and amending it, and
- Using existing powers to bring reservoir safety within the environmental permitting regime.
Scope of regulation
The Programme is considering some adjustments to the types of structures that fall outside the scope of reservoir safety regulation. The aim is to ensure that regulatory efforts are focused on those structures that pose the greatest risk to public safety.
New hazard classification
As part of Reservoir Safety Reform Programme, in March 2025 we completed the research and development project “Developing a new hazard classification for reservoir safety for England and Wales”.
A mixed disciplinary team of experts in reservoir safety, industry safety and risk management, Geographic Information System (GIS) and economic analysis, together with representative reservoir owners and engineers, have shaped the findings.
The project has provided key elements to support the reforms:
Policy development
We have used the research findings to inform the development of policy proposals for the future reservoir safety regime. Since the research project concluded, we have done further analysis of the top two hazard classification options, identified through the research. This work has considered the potential impacts and safety outcomes of each option and has helped further shape the policy proposals that will be presented as part of the public consultation. The consultation will provide an opportunity for stakeholders to share their views before any decisions are made.
Hazard Classification Research
The team of experts who worked on the research project, developed options for a new hazard classification system and proposed a new system which has four classes related to the level of hazard.
The current classification has just 'high risk' and 'not high risk' categories.
In the proposed new system this would be replaced with four hazard classes from Class 1 (highest risk) to Class 4 (lowest risk). The research proposed a new classification system which uses a combination of three factors:
The Research and Development project team reports summarise the development of the proposed new hazard classification system(External link), including the research process, key findings, and final proposals and recommendations.
A series of recorded presentations (https://sciencesearch.defra.gov.uk/) explain the research and development in more detail. Parts 1, 2 and 3 explain how the team has developed the new classification:
New framework for a risk-based and proportionate safety management system
The proposed classification with four classes recognises different levels of hazard. Consequences will be combined with an improved safety management system with safety management practices tailored to each class. For example, the level of supervision and inspection required may vary according to the reservoir class.
Developing this framework for the safety management system has focused on improving current practice and adding elements of good practice from other high-hazard sectors. We are proposing a greater emphasis on active risk management and introducing some new processes to help guide this in a structured way.
We are also aiming to update the existing record keeping requirements by replacing the Prescribed Form of Record with a Reservoir Safety Management Plan (RSMP). This will allow for a greater emphasis on clearly defined operation, maintenance and surveillance practices, ensure key safety information is available in one place and bring efficiencies to data storage and handling.
We are continuing to develop the details of the safety management system and how it might work for each class in practice.
Cost-benefit analysis
The research provides baseline estimates of the likely costs and benefits for the options considered for the new classification and safety management system. The analysis will be refined following consultation and ministerial decisions on the new system. This will inform a regulatory impact assessment (RIA) to accompany new legislation.
The benefits that we are seeking to deliver are:
A recorded presentation explains the cost benefit analysis research in more detail:
Small Raised Reservoirs (England only)
The forthcoming consultation will not propose extending reservoir safety regulation to include small raised reservoirs in England at this stage. A decision on whether to reduce the threshold and bring these reservoirs into a revised regulatory regime will be considered following further research and evidence gathering.
Safety regulation in England currently applies to raised reservoirs capable of holding 25,000m³ or more of water above ground.
We are undertaking further research over the next two years to gather more evidence about reservoirs storing between 10,000m3 and 25,000m3 of water above ground level, including their number, condition and the hazard they may pose to communities downstream. This will improve our confidence in the evidence base and cost-benefit analysis, helping inform a decision on whether to reduce the threshold to 10,000m3. Any decision would be about whether these reservoirs should be brought into a revised regulatory regime, rather than into the current regime.
The reservoir regulation threshold remains at 10, 000m³ in Wales.
Review of reservoir on-site emergency flood plans
Last year we undertook a survey to gather evidence of the costs and benefits of on-site emergency flood plans. The survey collected views and information from reservoir owners, engineers and emergency responders from lead local flood authorities and local resilience forums. The research report is available on Defra Science Search website: FD2742 - Evidence on costs and benefits of on-site emergency flood plans for reservoirs - FD2742
The research has been considered as part of the development of the safety management practices and Reservoir Safety Management plans. We intend that Emergency planning would be integrated within the Reservoir Safety Management Plans.
Records, registers and management systems
We are currently reviewing the management arrangements for reservoir safety. This includes improvements to systems to ensure operation, maintenance, monitoring and surveillance are being effectively delivered. Our review is looking to update the existing records and information keeping requirements to streamline data management practices and improve efficiency, and effectiveness.
We have collated and analysed valuable feedback received from extensive stakeholder engagement in Autumn 2024 and Spring 2025. This has helped refine policy proposals for a Reservoir Safety Case (incorporating risk assessment) and a Reservoir Safety Management Plan which integrate with the new hazard classes forming a proportionate management system. The plan replaces the existing prescribed form of record and documents management actions to ensure reservoir safety.
Modernising the legal framework
We have been considering the options for modernising the legal framework. Options include:
Our preferred approach is bringing reservoir safety regulation under the environmental permitting regulations (EPR) but this has not been decided.
There will be opportunities to share your views through stakeholder meetings.
