Proposed Reforms - What is likely to change?
- a new hazard classification (used to group reservoirs by how likely they are to cause harm)
- 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 – which will inform an impact assessment required for new legislation
- Part 1- Introduction to the hazard classification research
- Part 2 - Evidence gathered about safety management in other countries and sectors
- Part 3 - Developing the new hazard classification system
- 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.
One proposed change is the extension of regulation to smaller raised reservoirs in England with capacities between 10,000m³ and 25,000m³, which are already subject to regulation in Wales.
New hazard classification
As part of Reservoir Safety Reform Programme, the research and development project “Developing a new hazard classification for reservoir safety for England and Wales” completed in March 2025.
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:
The new classification and safety management system are research proposals and are not agreed policies at this stage.
Work on the details of the safety management system and how it might work for each class is ongoing. We are using the research to inform policy proposals for the whole safety regime. The proposals will be set out in the public consultation.
The Research and Development project reports summarise the development of the proposed new classification system, including the research process, key findings, and final proposals and recommendations. These are available on Defra’s Science Search website. FD2739 - Developing a new hazard classification for Reservoir Safety in England and Wales - FD2739
Hazard Classification
The research project developed options for a new hazard classification system and has proposed a system which has four classes related to 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 a system with four hazard classes from Class 1 (highest risk) to Class 4 (lowest risk).
The proposed new classification structure uses a combination of factors - dam height (H), reservoir volume (V), average societal loss of life (ASLL) and damages (other than loss of life). The height and volume are relevant for assessing the potential energy for escaping water and the ASLL and damages are relevant for assessing the downstream consequences. It has also been designed to include smaller raised reservoirs (SRR) between 10,000-25,000 m3.
The research project has also carried out an evaluation of current risk assessment methods, developed a method for reservoir design review and gathered evidence to inform the approach to onsite emergency planning.
A series of recorded presentations explain the research and development in more detail. Parts 1, 2 and 3 explain how the new classification has been developed:
New framework for a risk proportionate safety management system
The proposed classification with 4 classes recognising different levels of hazard and consequences will be combined with an improved safety management system with safety management practices tailored to each 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. Work on the details of the safety management system, including Reservoir Safety Management Plans (RSMP), and how it might work for each class has been taken forward.
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 later, following consultation and Ministerial decisions on the new system, to inform an impact assessment to accompany new legislation.
The benefits that we are seeking to deliver are:
Small Raised Reservoirs (England only)
The new hazard classification is designed to include reservoirs which are capable of holding 10,000 - 25,000 m3 water above ground level. We have used information collected earlier this year, as well as information about small raised reservoirs in Wales (which are already regulated) to help inform the development of the hazard classification.
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 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.
Over the coming months, there will be opportunities to share your views through stakeholder meetings, and the public consultation coming soon.
The Environmental Permitting (England and Wales) Regulations 2016 provides a modern regulatory framework for safety regimes for other sectors and industries which could be applied to reservoir safety. It has a hierarchy of permitting that includes exemptions, standard permits and bespoke permits, which we could apply to the different hazard classes to deliver a more proportionate approach.
If we use environmental permitting, the reforms can be introduced through regulations rather than needing a new bill in Parliament, and so the changes could be made to a more predictable timescale.
Environmental permitting would not change the reforms we need to make following the Independent Reservoir Safety Review Report, but it would provide a practical way of modernising the reservoir safety regime.