Report a reservoir incident
Source: gov.uk (2025-06-17)

Forms for reservoir operators to report incidents at dams to the Environment Agency.

If you own or operate a large raised reservoir you must report any reservoir safety incident by law if:
- an uncontrolled release of water occurred, or could have occurred
- you took emergency measures to stop an incident happening or worsening
You must send a preliminary incident report to us as soon as possible. Use Report a reservoir incident part A: preliminary report (https://assets.publishing.service.gov.uk/media/67d9499b4ba412c67701ecf2/Reservoir-incident-report-form-part-A-preliminary-report.pdf) to do this.

You have 12 months to investigate the causes and impacts of the incident and identify any lessons learned. You must send a final incident report with these learnings. Use Report a reservoir incident Part B: final report (https://assets.publishing.service.gov.uk/media/67d949a44ba412c67701ecf3/Reservoir-incident-report-form-part-B-final-report.pdf) to do this.

If you have not completed your investigations within 12 months you must update us before the deadline.

Tell us:
- what activities you have done
- your expected finish date
You should then send Report a reservoir incident Part B: final report (https://assets.publishing.service.gov.uk/media/67d949a44ba412c67701ecf3/Reservoir-incident-report-form-part-B-final-report.pdf) once you have finished your review.

These forms help you fill in the information we need. Use as much detail as you think is appropriate. You may find it useful to ask a qualified civil engineer to help with your form.

We encourage you to report your incident even if it:
- does not meet the above criteria
- occurred at a small raised reservoir
These lessons can help to prevent similar events happening where more serious consequences may occur.

What a reservoir incident is

The following definitions may help you understand what we mean by a ‘reservoir incident’.

Incident

An unplanned event which resulted in an uncontrolled or unintentional release of water, or damage to the site.

This could include a failure, or partial failure of any:
- dam
- wall
- embankment
- other water retaining structure
An unplanned event which resulted in one or more of the following:
- damage to the reservoir structure which may affect its safety
- an unintentional release of water resulting in negative impacts downstream such as flooding or physical damage
- emergency or precautionary measures being taken to stop the event worsening
Near miss

An unplanned event which did not result in an uncontrolled or unintentional release of water or damage to the site.

This may be due to:
- chance
- corrective action
- timely intervention
You may also use this category to report any unplanned or unexpected event from which wider learning can be gained.

Defects being addressed as measures in the interest of safety are reported and monitored through the inspection process. You should not record these as incidents or near misses.

You do not need to report minor defects picked up and rectified as part of routine maintenance. You may choose to do so if there is particular learning which may interest the industry.

If you want to report a safety concern at a reservoir or dam and you are not the operator, you should follow this guidance (https://www.gov.uk/guidance/reservoir-incident-and-safety-notify-the-environment-agency-of-a-potential-concern) . You can do this anonymously if you prefer.

Further information

Important lessons can be learnt from incidents. We share this learning to help reduce the risk of these events happening elsewhere. We will remove any identifiable information from your forms before we share them with the reservoir industry to ensure anonymity.

If you are unsure if you need to report your incident, contact us by emailing xxx@xxx.xx (mailto:xxx@xxx.xx) and we can advise you.