Exploring Manhole Inspection Technologies: From Remote Cameras to AI-Powered Condition Assessment

Manholes provide critical access to underground infrastructure, yet their condition is often overlooked compared to pipes. With growing demands on asset management and regulatory compliance, manhole inspections have become more crucial than ever. Fortunately, there is a range of technologies that now supports safer, faster, and more detailed manhole assessments.

Why Manhole Inspections Matter

Manholes are key infrastructure nodes in the underground network, enabling maintenance, ventilation, and emergency access. Structural deterioration, root intrusion, corrosion, and infiltration are all factors that could compromise the integrity of the system if left unchecked. Regular inspections on manholes are essential for:

• Preventing costly emergency repairs
• Ensuring worker safety and accessibility
• Supporting long term asset planning
• Meeting environmental compliance standards

Detailed and up to date data on manholes can help inform rehabilitation strategies, budget planning, and risk mitigation efforts for asset manager and councils.  

Traditional Methods vs Modern Approaches

Historically, manhole inspections were performed manually by crews, this would involve entering confined spaces armed with flashlights, clipboards, and basic photographic equipment. Whilst this hands-on approach provided direct access, there was also significant safety risks present, such as exposure to toxic gases, slips, or structural collapse. In addition, the outcomes of an inspection would depend on the individual inspector’s judgement, leading to inconsistent, subjective assessments and limited data for long term planning.

Modern technologies are now enabling safer, faster, and more consistent inspections, which is now allowing teams to gather high quality information whilst minimising risk.

• Pole cameras: These extendable telescopic devices with mounted high-resolution cameras allow inspectors to view and record the internal conditions from the surface, which reduces the need for entry and reduces inspection time.
• Confined space entry with CCTV: There are cases where entry is still required, inspectors are now equipped with high-definition cameras and gas detection tools, this allows a thorough visual documentation without compromising on the strict safety protocols.
• 3D laser scanning: This advanced technique captures highly detailed geometries of the manhole's interior with millimetre precision, allowing for accurate measurements, deformation detection, and the formation of virtual models (digital twins).  

Each method will vary in cost, accuracy, deployment time, and access requirements, but together they represent a major step forward. These tools are enabling a shift from paper-based inspections to data rich, low risk workflows that integrate with asset management systems.

Advances in Remote and Automated Tools

There are various innovative technologies available which supports with manhole inspections, these new ways are eliminating the need to enter manhole chambers. The available options are:  

• Zoom cameras: These cameras are high powered in optical zoom which allows detailed visual inspections from ground level.
• Manhole scanners: Rotating LiDAR sensors that create 3D models of the chambers interior.
• Drone-based inspections: In large-diameter or deep shafts, indoor drones offer safe, high-resolution image capture.

These solutions help to reduce risk, minimise traffic disruption, and support integration with asset databases and GIS systems.

Data Integration and Condition Assessment

Inspection technology is only a part of the equation, the ability to understand, manage, and act on inspection data is just as important. As the volume of inspection imagery and condition data grows, asset owners require more than just video collection tools. AI-powered platforms are now converting raw footage into actionable insights, enabling smarter infrastructure decisions.

These platforms enable utilities and councils to:

• Automatically detect and grade defects based on standardised coding frameworks (e.g. WSA, NASSCO).
• Align inspection results with asset registers by linking footage to the correct manhole IDs and location data.
• Generate standardised, auditable condition reports, allowing analysis on the network and comparisons easier.
• Prioritise rehabilitation using risk-based scoring models that take into consideration the severity, asset criticality, and historical data.

A good example of this in practice is City West Water in Victoria, Australia. They partnered with VAPAR to improve how they managed thousands of pipe and manhole inspections. By leveraging VAPAR’s AI-powered platform, they were able to:

• Rapidly process and classify defects from CCTV footage.
• Integrate results directly into their existing asset management systems.
• Create consistent condition grading and reporting across their network.
• Reduce turnaround time for inspections and improve rehabilitation prioritisation.

This approach enabled City West Water to shift from reactive to proactive maintenance approach, freeing up internal resources and supporting more accurate, evidence-based capital works planning.

Conclusion

With an expanding range of manhole inspection tools and methods available, selecting the right approach isn’t about chasing the latest trend, it’s about understanding the unique characteristics of your network. Factors such as manhole depth, structural condition, traffic access, safety risk, inspection frequency, and available budget will all influence which tools and methods will deliver the best outcomes for you.  

For some networks, a basic pole camera setup may provide the insights required for routine monitoring. Others may require high resolution 3D laser scanning or drone-based assessments to support with complex or hazardous environments. The integration of AI and cloud based platforms will further enhance value by enabling defect grading, centralised data storage, and data-driven rehabilitation planning.

Whether you’re trialling new technology on a pilot programme or scaling a city wide remote inspection strategy, the goal remains the same: to improve asset visibility, extend the infrastructure lifespan, and minimise the risk of unexpected failures.

Councils, utilities, and engineering consultants that proactively invest in these technologies are not just modernising their workflows, they are building resilience into their networks as well as reducing lifecycle costs, strengthening regulatory compliance, and most importantly, ensuring reliable service delivery for the communities they serve today and into the future.