Tank inspections Drone Guide

Storage tanks are essential infrastructure across the utilities sector. Water companies, wastewater operators, energy providers, industrial utilities and municipal authorities rely on tanks to store drinking water, process water, wastewater, chemicals, fuels and other operational materials.

These assets require regular inspection to understand their condition and identify visible deterioration before it develops into a larger maintenance problem.

Traditional tank inspections can be challenging. External inspections may require scaffolding, rope access, elevated platforms or personnel working at height. Internal inspections can be considerably more complex, potentially involving confined-space procedures, specialist access equipment, cleaning, isolation and extended periods when the asset is unavailable.

Drones provide another inspection method.

High-resolution cameras, optical zoom, thermal imaging, LiDAR and specialised confined-space drones can collect information from external surfaces and, in suitable environments, tank interiors. The objective is not to eliminate conventional inspection or engineering assessment, but to reduce unnecessary access and provide engineers with better information about where closer investigation may be required.

For water utilities, wastewater companies, energy providers and industrial operators, drone inspections can form an important part of a risk-based asset-management programme.

What Is a Drone Tank Inspection?

A drone tank inspection uses an uncrewed aircraft to collect visual or sensor information about a storage tank and its associated infrastructure.

For external inspections, the drone flies around the asset while collecting high-resolution imagery.

For internal inspections, a specialised aircraft may enter an appropriately prepared tank to inspect walls, roofs, structural elements and other accessible components.

The resulting information is reviewed by engineers or qualified inspectors.

Drone imagery identifies visible conditions; engineering professionals determine their significance.

Why Use Drones for Tank Inspections?

The main advantage is access.

Tanks can be tall, enclosed or difficult to reach safely. Obtaining a close view of upper walls and roof structures can require substantial equipment.

A drone can position a camera near many areas of the asset without requiring a person to occupy the same location.

This can reduce the amount of work at height required during initial visual assessment.

It can also help maintenance teams understand where specialist access is actually necessary.

Water Storage Tanks

Water utilities operate many types of storage infrastructure, including service reservoirs, elevated tanks, water towers and treatment-facility tanks.

Drones can document visible external condition and associated infrastructure.

High-resolution imagery can provide information about roofs, walls, access structures and external fittings.

Repeated surveys allow asset managers to compare condition over time.

Wastewater Tanks

Wastewater facilities can contain settling tanks, process tanks, digesters and other structures.

Many of these assets are large and difficult to inspect from ground level.

Drones can provide aerial imagery of external surfaces and accessible upper structures.

The same flight can also document surrounding pipework, walkways and other infrastructure.

Elevated Water Tanks

Elevated tanks are particularly suitable for drone inspection because much of the structure is difficult to observe closely from the ground.

A drone can capture detailed imagery of the tank, support structure, roof and other visible components.

Optical zoom allows some inspections to be conducted from greater stand-off distances.

This can significantly improve the quality of information available before personnel are sent to work at height.

Tank Roof Inspections

Tank roofs are exposed to weather and environmental conditions.

Drone imagery can document visible corrosion, coating deterioration, debris, standing water or other surface conditions.

The aircraft can capture both overview imagery and detailed photographs.

Maintenance teams can use this information to determine where closer inspection may be necessary.

Tank Wall Inspections

External tank walls can be systematically photographed.

The flight plan can divide the wall into overlapping sections so that the complete surface is documented.

Images can be associated with specific asset locations.

This makes it easier to compare the same section during future inspections.

Corrosion Identification

Corrosion is an important concern for many metallic tanks.

High-resolution RGB cameras can identify visible corrosion where surface appearance has changed sufficiently.

Drone imagery can document the location and approximate extent of visible areas.

However, a camera cannot determine remaining wall thickness.

Ultrasonic testing or other appropriate non-destructive testing methods may still be required.

The drone helps identify where these measurements should be concentrated.

Coating Condition

Protective coatings help shield tank surfaces from environmental exposure.

Drone imagery can reveal visible peeling, blistering, fading or damaged areas.

A systematic survey can create a map of coating condition across the structure.

This can help operators prioritise maintenance rather than treating the complete asset uniformly.

Crack Identification

High-resolution imagery may reveal visible cracking in concrete tanks or associated structures.

The effectiveness depends on crack size, camera resolution, lighting, viewing angle and flight distance.

Potential cracks identified from imagery should be assessed by qualified personnel.

Drone inspection provides screening and documentation rather than an automatic structural diagnosis.

Joint and Seam Inspection

Welds, joints and seams can be important inspection locations.

A drone can collect close visual imagery where safe operating distances permit.

Optical zoom can provide additional detail.

Any suspected defect should be investigated using the appropriate engineering inspection technique.

Bolts and Connections

Large tanks and their supporting structures may contain numerous mechanical connections.

Drone imagery can document visible bolts, brackets and connections in difficult-to-access locations.

This can help inspectors identify missing components, visible corrosion or other conditions requiring physical investigation.

Access Ladder Inspections

Tank ladders and access structures are themselves safety-critical assets.

Drones can photograph ladders, platforms, handrails and cages.

This allows maintenance teams to assess visible condition before personnel use the access system.

Direct inspection may still be required before equipment is certified as safe.

Walkways and Platforms

Elevated platforms and walkways can be difficult to inspect from below.

Drone imagery provides alternative viewing angles.

Visible corrosion, damage or debris can be documented.

The resulting photographs can form part of an asset-maintenance record.

Internal Tank Inspections

Internal inspection can be one of the most challenging tank-maintenance activities.

Depending on the tank and its contents, entering the structure may involve confined-space procedures and extensive preparation.

Specialised indoor drones can provide an initial visual assessment in suitable environments.

They can inspect walls, roofs and structural components without requiring personnel to occupy every inspection location.

This does not remove the need for conventional inspection where physical measurements are required.

Confined-Space Drones

Indoor inspection drones are often designed differently from conventional outdoor aircraft.

Protective cages can surround the propellers and airframe.

This allows the drone to tolerate limited contact with surfaces while operating in confined environments.

Collision-tolerant designs can be particularly useful inside tanks, vessels, tunnels and other GPS-denied structures.

GPS-Denied Navigation

Satellite navigation may be unavailable inside a steel or concrete tank.

Indoor drones therefore require alternative navigation methods.

Visual-inertial navigation, LiDAR, optical-flow sensors and other technologies can support positioning.

The exact solution depends on the aircraft and operating environment.

Reliable navigation is particularly important where the pilot cannot directly see the drone.

Internal Roof Inspection

Tank roofs can contain beams, supports, welds and other structural elements.

A confined-space drone can provide close visual information about accessible components.

This can reduce the need to construct temporary access solely for an initial visual survey.

Engineers can then determine which areas require direct inspection.

Internal Wall Inspection

The drone can systematically inspect interior wall surfaces.

High-resolution imagery can document visible corrosion, coating damage, deposits or other conditions.

Video can be geographically or structurally referenced where appropriate.

This creates a digital record of internal condition.

Sediment and Deposits

Some tanks accumulate sediment or other deposits.

Where the operating environment allows drone inspection, imagery may provide information about visible accumulation.

However, visual observations alone cannot necessarily determine material composition or depth accurately.

Additional inspection methods may be required.

Thermal Imaging

Thermal cameras can provide additional information during certain external tank inspections.

Temperature patterns may help identify areas requiring closer investigation.

For example, differences across a tank surface may sometimes relate to contents, insulation or environmental effects.

Thermal imagery must be interpreted carefully because sunlight, wind and surface materials can significantly influence readings.

Insulation Inspection

Insulated tanks can experience deterioration that is not immediately visible.

Thermal surveys may provide indications of unusual surface-temperature patterns.

These can help maintenance teams identify areas requiring further inspection.

Thermal imaging should be treated as a screening technique rather than definitive proof of a particular defect.

Leak Detection

Visible leakage can sometimes be identified using RGB imagery.

Thermal sensors may provide additional information where escaping material creates a detectable temperature difference.

However, small or hidden leaks may not be visible from a drone.

Specialist leak-detection equipment may still be necessary.

Water-Level Observation

Some open tanks or reservoirs allow water levels to be observed directly.

Drone imagery can provide an overview of the asset and visible water surface.

For operational measurement, dedicated level sensors are normally more appropriate.

The drone provides supplementary visual information rather than replacing instrumentation.

LiDAR Tank Inspection

LiDAR can create detailed three-dimensional representations of structures.

For external tank inspections, a LiDAR-equipped drone can map the tank and surrounding infrastructure.

Specialised indoor LiDAR systems can also map certain tank interiors.

The resulting point cloud provides a geometric record of the asset.

3D Modelling

Photogrammetry can transform overlapping drone photographs into a three-dimensional model.

The model allows engineers to view the tank from different angles and associate observations with specific locations.

This can improve collaboration between inspection, engineering and maintenance teams.

Repeated models can also provide a visual history of the asset.

Digital Twins

Drone-generated imagery, point clouds and inspection observations can contribute to a digital twin.

The digital representation can include the tank geometry, maintenance history, inspection results and asset information.

Future inspections can be linked directly to the same model.

This creates a more structured approach to long-term asset management.

Photogrammetry

Photogrammetry is particularly useful for documenting large external surfaces.

The drone captures overlapping photographs from multiple positions.

Processing software identifies common points and reconstructs the geometry.

The result can include orthographic imagery, 3D models and surface measurements.

Accuracy depends on flight planning, camera quality and survey-control methods.

Automated Defect Detection

Artificial intelligence can assist with reviewing large quantities of inspection imagery.

Computer vision may highlight areas showing visual characteristics associated with corrosion, coating damage or cracking.

This can reduce the amount of imagery requiring initial manual review.

However, AI findings should be verified by qualified inspectors.

Comparing Inspections Over Time

The real value of drone inspection increases when surveys are repeated consistently.

Images from one year can be compared with later inspections.

A small corrosion area can be monitored to determine whether it appears to be expanding.

Coating deterioration can also be tracked.

This moves the inspection programme from isolated observations towards condition monitoring.

Asset Management Integration

Drone inspection information can be connected with utility asset-management platforms.

Each tank can have its own digital record.

Images, defects, engineering observations and maintenance actions can be associated with the asset.

This improves traceability and helps operators prioritise investment.

GIS Integration

Utilities often manage infrastructure using Geographic Information Systems.

Tank locations, pipelines, treatment facilities, pumping stations and other assets can be displayed geographically.

Drone inspection results can be linked directly to individual assets.

This allows engineering teams to access aerial information through existing infrastructure-management systems.

RTK Positioning

RTK-enabled drones can provide more consistent geographic positioning for external surveys.

This is useful when repeat inspections need to capture similar locations.

Accurate positioning also improves mapping and 3D modelling.

The required survey accuracy should be determined by the intended engineering application.

Automated Flight Planning

Large tanks can be inspected using repeatable automated flight paths.

The drone can follow predefined routes around the asset while maintaining appropriate distances.

This helps ensure consistent image overlap and coverage.

Future inspections can repeat similar routes, making comparison easier.

Operators must still maintain appropriate oversight.

Drone-in-a-Box Tank Monitoring

Utilities with large facilities may eventually use permanent automated drone stations.

A Drone-in-a-Box system can store and charge an aircraft at a treatment plant or industrial site.

The drone can conduct scheduled external inspections of tanks and other infrastructure.

After completing the mission, it returns to the docking station.

This can make routine visual monitoring more frequent.

Multi-Asset Utility Inspections

A major advantage of utility drones is that the aircraft does not need to inspect only tanks.

The same platform can inspect pipelines, roofs, solar installations, substations, reservoirs, treatment structures and other infrastructure.

This improves utilisation of the drone programme.

Specialist confined-space aircraft can then be maintained for internal inspections.

Water Utility Applications

Water companies can use drones across storage, treatment and distribution infrastructure.

Tank inspections can be combined with reservoir surveys, pipeline corridor mapping and treatment-plant inspections.

This creates a wider aerial asset-management programme.

Data can be standardised across multiple infrastructure categories.

Wastewater Utility Applications

Wastewater facilities contain many structures that are difficult to inspect.

Drones can survey tanks, clarifiers, digesters, roofs and surrounding infrastructure.

The aerial perspective provides an overview of the complete facility.

This can help maintenance teams coordinate work across interconnected assets.

Industrial Utility Applications

Large industrial facilities often operate their own water, wastewater and energy infrastructure.

Drone inspection programmes can therefore support both production equipment and utility assets.

A single aerial inspection team may cover tanks, pipework, roofs, flare structures and other infrastructure.

This increases the potential return on investment.

Safety Benefits

Reducing unnecessary work at height is one of the strongest advantages of drone inspection.

A drone can perform an initial visual survey before scaffolding, rope access or elevated platforms are deployed.

For internal inspections, specialised drones can also reduce the need for immediate confined-space access.

Personnel can then be sent only to locations where physical measurements or maintenance are required.

This creates a more targeted inspection process.

Reducing Downtime

Traditional inspection may require significant preparation and asset downtime.

Drone surveys can sometimes be completed more quickly, particularly for external visual inspections.

Internal inspections may also provide useful preliminary information before more invasive work begins.

Reduced downtime can be especially valuable for operationally important utility infrastructure.

Inspection Documentation

Drone imagery provides a detailed visual record.

Photographs and video can be associated with the inspection date and asset.

Engineers who were not physically present can review the information later.

This improves collaboration and provides evidence for future condition comparisons.

Challenges and Limitations

Drones cannot perform every type of tank inspection.

A camera cannot measure metal wall thickness unless combined with appropriate specialised contact or NDT technology.

Hidden defects may not be visible.

Internal environments can contain hazardous gases, dust, moisture or other conditions unsuitable for standard drones.

Steel structures can affect communications and navigation.

Outdoor flights may also be restricted by wind, rain or nearby infrastructure.

Qualified engineering assessment remains essential.

Regulatory and Safety Considerations

Outdoor drone operations must comply with applicable aviation requirements.

Internal tank flights may fall outside normal aviation environments but introduce different industrial safety considerations.

Operators need to understand confined-space hazards, explosive atmospheres and facility procedures.

The drone itself must be suitable for the environment in which it is being operated.

The Future of Tank Inspection Drones

Tank inspection is moving towards increasingly digital and automated asset management.

External drones will conduct repeatable high-resolution surveys.

Confined-space drones will provide increasingly sophisticated internal mapping.

LiDAR and photogrammetry will create detailed 3D models.

Artificial intelligence will assist with identifying and tracking visible defects.

Inspection information will feed directly into digital twins and maintenance platforms.

Rather than receiving a collection of photographs, engineers could receive a digital tank model showing the location, classification and inspection history of every identified area of concern.

Autonomous drones could monitor external tank condition routinely, while specialist inspection teams concentrate on detailed engineering assessment.

Conclusion

Tank inspection is a strong application for drone technology across water, wastewater, energy and industrial utilities.

Storage tanks can be large, elevated and difficult to access, making conventional inspection time-consuming and potentially hazardous.

Drones provide a flexible method of collecting high-resolution information from external surfaces and, using specialist platforms, certain internal environments.

RGB cameras can document visible corrosion, coating deterioration and structural condition. Thermal sensors can provide additional surface-temperature information. LiDAR and photogrammetry can create detailed three-dimensional models, while AI can help engineers process large inspection datasets.

The most important advantage is not simply replacing an inspector with a drone. It is reducing unnecessary access while giving inspectors better information about where physical investigation is actually required.

For water companies, wastewater utilities, energy providers, municipalities and industrial operators, drone-based tank inspection can contribute to safer inspections, improved documentation, reduced downtime and more data-driven asset management.