Understand your reservoir inspection report

If you haven’t appointed an Inspecting Engineer you should read our guidance on how to arrange a reservoir inspection.

After your reservoir has been inspected, you should meet with the Inspecting Engineer and your Supervising Engineer. This can be in person, by phone or online. The meeting will help you understand what the inspection report is likely to contain so you can prepare for any work required. The meeting should be prompt, particularly if immediate actions were identified and within one month of the inspection.

At the meeting you should check the Inspecting Engineer explains:

  • the initial findings, urgent actions and immediate precautionary measures required
  • the risks at your reservoir and any provisional recommendations with start and finish dates for discussion
  • any work required should start immediately and that the completion target date does not represent the urgency but is there as a trigger date for enforcement action by us
  • considerations for how you may prioritise work across other reservoirs you may have
  • answers any questions you may have

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

Review your inspection report

Your Inspecting Engineer should provide a report as soon as practicable after the inspection. If this takes more than six months, they must write to us and explain their reasons for the delay.

You should review the draft report to make sure you understand what it says. Make sure you understand the implications of any recommendations for monitoring, maintenance or safety works which are required. Discuss issues with the Inspecting Engineer and ask for a revised version if appropriate. The engineer will try to accommodate such requests but also have a duty to ensure the reservoir is kept safe. They may need to refuse requests if they consider it unsafe to do so.

The inspection report will describe your reservoir, summarise your management of it and provide the findings of the inspection. It will generally provide the following information:

  • A summary of previous reports and the information reviewed as part of the inspection
  • A description of the landscape, rainfall catchment and underlying geology
  • A description the original construction and any alterations, along with any other significant works
  • A description of the dams or embankments, spillways, pipework, valves and outlets
  • Comments on the areas downstream of the reservoir

The Inspecting Engineer will assess the extent to which the reservoir structures meet current standards especially in how well it may hold and convey different water levels up to extreme floods. The report will contain the engineer’s findings which describe any shortcomings in design, signs of deterioration or improvements to be made. These will be grouped as:

  • Reservoir safety risk analysis and potential failure modes
  • Adequacy of the dams or embankments
  • Adequacy of the reservoir to withstand seismic earth tremors or earthquakes
  • Adequacy of inlet and outlet pipework or channels to ensure water flows are controlled
  • Commentary on your effectiveness of management and supervision including water level monitoring, instrument readings and record keeping
  • Emergency planning and adequacy of your flood plan.

The Inspecting Engineer will specifically comment on the status of any previous measures to be taken in the interests of safety. You should pay close attention to recommendations under the following headings:

Recommended measures to be taken in the interests of safety

Measures to be taken in the interests of safety are often called MIOS. Although they are called recommendations, they are legally required, and you must carry them into effect by the date given by the Inspecting Engineer.

MIOS are important works, and you should carry out the work as soon as practicable after the inspection has been completed. Your Inspecting Engineer should provide you with enough information at the post-inspection meeting to enable you to start planning.

The MIOS due date may be years away, but you must start work straight away. Other permissions may be needed, such as planning consent from your Local Planning Authority, Water Resources licence or Environmental Permit from us. These often require advice and planning and will take many months to secure.

You must appoint a qualified civil engineer (QCE) from the appropriate panel to provide a certificate of completion. This engineer can be the same as the Inspecting Engineer but does not have to be.

You can use a 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.

You should appoint the QCE within 14 days of receiving the inspection report. Getting a QCE appointed at an early stage will help the design and confirm that your proposed work will satisfy the recommendation. If you appoint a QCE part way through completing the MIOS, you may have to redesign or undo work to satisfy them as to the quality.

Recommendations for the maintenance of the reservoir

These are essential activities to prevent deterioration. These recommendations are legal requirements which you must complete and continue to manage to the standard recommended.

You do not need to acquire a certificate of completion, but your Supervising Engineer has a duty to provide a statement on the status of maintenance which is copied to us, and we may check progress at any time.

Matters to be watched by the Supervising Engineer

You are expected to manage the reservoir and are responsible for its safety. Your Supervising Engineer is tasked with watching specific matters identified by the Construction or Inspecting Engineers, and to monitor how well you are managing them.  We advise you to discuss these matters with your Supervising Engineer, so you understand what to do properly.

Directions for monitoring and records

The Inspecting Engineer may prescribe anything which needs monitoring, the records to be kept, and the method and frequency of data collection. You must carry out all these activities and record them in your Prescribed Form of Record.

Other measures and matters of general maintenance and public safety

These measures will help you manage your reservoir safely. They do not require certification but may be examined by your Supervising Engineer or by one of our Officers.

Recommendation for the time of the next inspection

The Inspecting Engineer must include a date by when your reservoir must be inspected again.

Information and data security

The final Inspection Report is an important document which you should keep for the lifetime of the reservoir. It contains sensitive information about your reservoir and personal information. We advise you not to share the report, other than with those who have a genuine need to know, for example your Supervising Engineer and operational staff.

Compliance and enforcement

We receive a copy of the inspection report. We consider the Inspecting Engineer’s findings and recommendations to be important information about the safety of your reservoir.

We record and track the recommendations made by the Inspecting Engineer. You should provide us with regular updates to keep us informed of your progress. We may arrange to visit your reservoir or speak with your Supervising Engineer to satisfy us satisfactory progress is being made.

We can serve an enforcement notice on you requiring the completion of matters to be taken in the interests of safety. If you fail to carry out the Inspecting Engineer’s recommendations, you could be committing criminal offences.

Appoint a referee to determine disagreements

In the event you disagree with an inspection report, you may wish to appoint a referee to determine an independent decision. You can appoint a referee if you disagree with any of the following recommendations as to:

  • measures to be taken in the interests of safety 
  • the maintenance of the reservoir, or
  • the time of the next inspection.

The referee must be an independent All Reservoirs Panel Engineer (see above) appointed by agreement between you and the engineer making the recommendation. The appointment must be agreed within 40 days of the date of the inspection report.

If you cannot reach an agreement within 40 days, you can request a referee is appointed by the Welsh Ministers. This must be done within 50 days of the date of the inspection report. Contact us for more details about this.

The appointed referee will review the recommendation and has the power to modify the report as he thinks fit. The referee will issue a certificate stating whether the report has been modified, or not and will revise the Inspecting Engineer’s certificate. The modified report and certificates will be sent to you and copied to us.

If you have cause to appoint a referee, you should notify us for information, but we do not have the authority to appoint a referee for you.


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