If you own or manage a High-Risk Reservoir, you must arrange to have it inspected at any of the following times:

  • Within one year of your reservoir being designated by us as a High-Risk Reservoir
  • When your Supervising Engineer recommends an inspection
  • Before the date recommended by the last Inspecting Engineer
  • No later than 10 years from the last inspection
  • Within six months of any work which may affect reservoir safety. This rule doesn’t apply if the work undertaken was supervised by an Inspecting Engineer or you are altering the reservoir’s capacity under the supervision of a Construction Engineer.

Appoint an Inspecting Engineer

You must use an Inspecting Engineer who is appointed by Government to a panel of reservoir engineers specialising in the type of reservoir you have. There are three panels to consider:

You can use an All Reservoirs Panel Engineers (ARPE) for any type of reservoir. An ARPE can also act as a referee if you dispute an inspection report, see our guidance on understanding your inspection report.

Find a list of all reservoirs panel engineers on Gov.uk

You can use a Non-Impounding Reservoirs Panel Engineer for reservoirs which do not directly impede a river or stream, but which are filled by pumping or diverting water.

Find a list of non-impounding reservoir panel engineers on Gov.uk

You can use a Service Reservoirs Panel Engineer for brick, or concrete non-impounding reservoirs which typically store and supply drinking water.

Find a list of service reservoir panel engineers on Gov.uk

If you do not know what type of reservoir you have, you should speak with your Supervising Engineer or contact us.

Allow plenty of time to find and appoint an engineer. We advise you make your first enquiries at least 12 months in advance, so you are confident your reservoir will be inspected before the due date.

Inspecting Engineers work across the UK and worldwide. When you look for an engineer, you may not find one located nearby but they all travel regularly and will be able to advise you. You should approach several engineers to understand any differences in the terms and conditions of their appointment.

When you have appointed an Inspecting Engineer, you must notify us of it within 28 days. You must tell us:

  • The name and location of the reservoir to be inspected
  • The name and business address of the engineer you have appointed
  • The reservoir engineering panel to which they are appointed
  • The date you appointed the engineer
  • The proposed date for the inspection
  • Your name and contact details

Prepare a reservoir information pack

Before an inspection, your Inspecting Engineer will need to review information about the reservoir. If the Inspecting Engineer requests information to help their inspection, you must provide it to them.

Find further guidance on how to prepare a pre-inspection information pack.

What happens during an inspection?

The Inspecting Engineer will examine the reservoir and the documents which relate to its construction, alteration, operation and records of maintenance and monitoring. They will assess the ability of your reservoir to withstand stresses caused by different level of flood and compare this with the population and properties which may be at risk downstream.

The Inspecting Engineer will assess the capacity and integrity of any spillways or other overflows using all available information including hydraulic, structural, geotechnical and other aspects that could affect its safety.

The Inspecting Engineer may recommend how you and your Supervising Engineer should inspect the spillway, and how often you should do this. They may also advise you to arrange direct access into the spillway for close inspection or suggest alternative means.

We provide separate guidance for Inspecting Engineers.

For more detailed guidance we recommend the following documents

  • Spillway design guide
  • Spillway examination guide
  • Spillway failure mechanisms guide

Find guidance on Spillway design, examination and failure mechanisms on GOV.UK

The Inspecting Engineer may ask you to demonstrate the use of valves or other equipment and enquire about operational and maintenance schedules. They will want to examine your Prescribed Form of Record and should ask to see your flood plan for dealing with emergencies and how you test this.

If the Inspecting Engineer has any immediate concerns, they should tell you on the day.

If your reservoir is more complex, the Inspecting Engineer may need to visit more than once. The inspection is not complete until all necessary visits have been made.

After an inspection

When the inspection is complete, you should arrange a formal meeting with the Inspecting Engineer and your Supervising Engineer. This can be in person, by phone or online. The meeting should be prompt, particularly if immediate actions were identified and, in any case, the meeting should be held within one month of the inspection.

At that meeting the Inspecting Engineer:

  • discuss the initial findings, urgent actions and immediate precautionary measures required
  • explain the risks at your reservoir and any provisional recommendations with start and finish dates for discussion
  • explain that any work required should start immediately and that the completion target date is the trigger for enforcement action and does not represent the urgency
  • enquire about other reservoir you may have so that overall risks can be managed
  • discuss anything else to do with completing the inspection

The Inspecting Engineer should make a written record of the meeting and share them with you. You may wish to make your own notes.

Read our further guidance to understand your reservoir inspection report.


If you do not appoint an Inspecting Engineer and obtain an inspection report when it is due or fail to provide the information and facilities to allow the engineer to complete their inspection, you could be committing criminal offences.

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