Challenges and Solutions for Maintaining Aging Infrastructure: Recent Initiatives in the Civil Engineering and Construction Industry

Japan’s social infrastructure, much of which was developed during the period of high economic growth, is aging rapidly, and the burden of maintenance is increasing year by year. In particular, water and sewer infrastructure—critical lifelines that support people’s daily lives—face challenges such as accident risk, rising maintenance costs, and a shortage of personnel. This article, aimed at professionals in the civil engineering and construction sectors such as municipal infrastructure managers, construction consultants, and technicians from small-to-medium construction firms and large general contractors, outlines the current state and challenges of maintaining aging infrastructure and introduces solutions through the application of cutting-edge technologies and public–private partnership models. At the end of the article, we touch on how simple surveying using smartphones and high-precision GNSS receivers—LRTK—can assist water and sewer maintenance and consider future prospects.

Current State and Challenges of Maintaining Aging Water and Sewer Infrastructure

Across Japan, the aging of water and sewer pipelines and treatment facilities has become serious. Because many water supply and sewer systems were concentratedly developed in the 1960s and 1970s, they are now simultaneously reaching the time for replacement. The proportion of pipelines that have exceeded their service life (statutory service life of approximately 40–50 years) is increasing year by year, reaching over 20% in the early 2020s. Pipes that have exceeded their service life continue to be used, and nationwide there are more than 20,000 leakage and breakage incidents annually, raising concerns about declining infrastructure reliability. Aging infrastructure can also amplify damage in large-scale disasters. For example, the 2024 Noto Peninsula earthquake caused severe damage to water and sewer facilities, resulting in water outages for about 140,000 households. Given these circumstances, planned renewal and maintenance of aging infrastructure has become an urgent issue.

Main challenges:

• High burden of monitoring and inspection: Regular monitoring and inspections are essential to detect infrastructure deterioration early. However, conventional inspections rely heavily on visual checks and sounding tests by human inspectors, making it difficult to assess every corner of water and sewer pipelines and facilities. For instance, inspecting extensive pipeline networks requires large numbers of personnel and time, and nighttime work or traffic control may be needed to ensure worker safety. As a result, inspection frequency and scope are limited, increasing the risk of overlooking deterioration and delaying responses.

• Costs of repair and renewal and financial burden: Repairing and refurbishing aging infrastructure requires enormous funds, but many municipalities lack financial flexibility. Water tariff revenues have tended to decline due to population decline and stronger water-saving awareness, while investment for renewing aging facilities is increasing, worsening the revenue-expenditure balance. A Ministry of Internal Affairs and Communications survey reported that about 12% of water supply entities were operating at a deficit in fiscal 2022. At the current renewal pace, it is estimated that it would take more than 100 years to replace all water pipes, suggesting that continuing with conventional methods may render infrastructure maintenance untenable.

• Shortage of engineers and skills transfer issues: On-site maintenance faces a severe shortage and aging of skilled personnel. The number of staff engaged in waterworks peaked at about 80,000 in 1990 but fell to about 72,000 by the 2020s. In particular, small local utilities are seeing pronounced workforce shortages as veteran staff retire without sufficient new hires. As the burden of balancing daily operations with vast equipment management increases for a limited workforce, the know-how of experienced personnel becomes tacit and difficult to pass on. Traditional manpower-intensive approaches have limits in efficiency, making DX (digital transformation) in maintenance and management necessary to reduce labor and standardize work.

As described above, the field dealing with aging infrastructure faces a triple threat of heavy inspection burdens, insufficient renewal funds, and shortages of personnel and technical capability. To overcome these challenges, the civil engineering and construction industry has recently begun adopting various cutting-edge technologies and new business models to improve the efficiency and sophistication of maintenance and management.

Use of Advanced Technologies to Improve Maintenance Efficiency

Rapidly advancing technologies are bringing innovation to infrastructure maintenance. Technologies that once seemed like science fiction—AI, IoT, sensors, robots, drones, LiDAR, 3D models, and cloud integration—are being applied in practice, and automation of inspections and data-driven preventive maintenance are becoming realities. Below are the main advanced technologies useful for maintaining water and sewer infrastructure and examples of their application.

Infrastructure condition monitoring with AI and IoT sensors

AI (artificial intelligence) and IoT (Internet of Things) technologies offer new possibilities for monitoring infrastructure conditions and detecting anomalies. For example, in leakage detection for water pipes, attempts are underway to use satellite data analyzed by AI to broadly identify leaks that are not visible from the surface. By capturing moisture distribution with airborne microwave data and using AI to distinguish between rainwater and leakage, it is possible to more efficiently narrow down underground leak areas. Technologies have emerged that can extract suspected leak locations within an area roughly 200 m in diameter, which is expected to greatly reduce the effort required for wide-area leak surveys.

AI is also being used to predict deterioration of distribution and sewer pipes. By analyzing big data—such as pipe installation year, material, and soil environment—AI can estimate how much each pipe has deteriorated and which segments are at high risk of failure. This enables prioritizing sections that require renewal in advance and supports planned pipeline replacement. In fact, some municipalities have introduced systems that compute pipe break probabilities with AI and reflect them in renewal planning. Because decisions on where limited budgets will be most effective can be made based on data, waste-free preventive maintenance becomes possible.

Moreover, real-time monitoring using IoT sensors is spreading. Network cameras, vibration sensors, and pressure sensors installed at treatment plants and pump stations can monitor equipment operation and abnormal vibrations 24/7. For example, NTT Group and Metawater Corporation have started demonstration experiments to automate巡回 inspections of water and sewer facilities, developing systems that analyze data from IoT sensors and cameras installed on-site with AI to automatically detect abnormal signs. If realized, this would enable smart maintenance management that allows remote monitoring of facility conditions without personnel being permanently on-site and rapid response in case of abnormalities.

Inspection automation using robots and drones

In the realm of physical infrastructure inspection, the introduction of robot technologies and drones (unmanned aerial vehicles) is advancing. These systems can perform inspections in dangerous or confined spaces in place of humans, improving safety and work efficiency.

Ground patrol robots and underwater robots: For inspections inside water and sewer facilities, quadruped robots and underwater robots are attracting attention. For example, some sewage treatment plants have introduced quadruped patrol robots to inspect equipment across large facilities; robots automatically read values from sensors on each device and collect data, reducing the need for personnel to make rounds. If robots can operate in places with poor footing or in darkness, they can reduce worker burden and hazards. Similarly, robotic camera units that travel underwater have been trialed in sewer pipes to investigate internal cracks and sediment conditions. Narrow sewer pipes that previously required workers to descend into manholes can be inspected by robots without the risk of human casualties.

Drone inspections: Drones excel at aerial and enclosed-space imaging, revolutionizing inspections of locations that were previously hard for humans to access. For example, for inspections of aqueducts that span rivers or elevated water tanks, drones equipped with high-resolution cameras can capture imagery without erecting scaffolding or using aerial work platforms. The Kanagawa Prefectural Waterworks has introduced drones for inspecting bridges and reservoirs, enabling assessment of deterioration from various angles. This allows image analysis to detect fine corrosion or cracks that humans may overlook and supports early repairs.

Advanced cases have also emerged using small flying robots known as spherical drones for internal inspection of sewer pipes. In Himeji City, Hyogo Prefecture, a demonstration in 2025 deployed the roughly 40 cm-diameter spherical drone “ELIOS3” for autonomous flights and filming in pipes that are difficult for humans to enter. Traditional human inspections of sewer pipes faced risks from toxic gases (hydrogen sulfide) and limitations in coverage when using camera-mounted inspection carts that could not overcome steps; drones can fly over obstacles and capture footage of pipe interiors in detail. The result confirmed more efficient initial diagnostics and improved safety, and full integration into regular inspections is expected going forward.

Thus, robot and drone technologies are enabling inspections in areas that are inaccessible, invisible, or hazardous to humans, achieving labor savings and higher-level inspections. Collected images and sensor data are stored in the cloud and analyzed by AI, leading to further efficiency gains.

Data sharing through digital twins and cloud utilization

Centralized data management and remote information sharing are also important in infrastructure maintenance. Recently, digital twins—3D models that replicate real structures in virtual space—based on BIM/CIM and GIS are being developed. High-precision 3D data obtained via LiDAR (laser scanners) and photogrammetry are used to create detailed models of water and sewer facilities and terrain, and there is a growing number of cases in which these models are managed in the cloud. For example, in Kanda Town, Fukuoka Prefecture, the water pipeline maps were migrated from paper to digital maps, integrating plan views, photos, and inspection history in the cloud so that staff can share infrastructure information in real time. By plotting deterioration locations and repair histories on a digital map, new personnel can immediately understand past conditions, aiding planned maintenance management.

There are also examples of remote monitoring and work support using cloud platforms. Kawakita Town, Ishikawa Prefecture, visualized various sensor values and equipment operation statuses of its water treatment plant in a cloud-based monitoring system and implemented an alert system for responsible staff in case of abnormalities. This enables a small team to oversee multiple facilities and improves emergency response speed. In addition, the Yokohama Waterworks Bureau has conducted pilot implementations of remote work support using AR (augmented reality) smart glasses. Field workers wearing smart glasses can stream on-site images in real time to veteran technicians at headquarters, who can provide instructions using voice and AR markers. This allows sharing of expert knowledge remotely, enabling “multiple experts’ wisdom at a single-field site” and facilitating labor savings without reducing the quality of complex tasks and troubleshooting.

Private companies are also offering cloud services for infrastructure management. For example, Mirait One Co., Ltd. provides a “Water DX Solution” that supports water and sewer entities from investigation and diagnosis through construction and maintenance. This service consolidates data collected by sensors and inspections into the company’s cloud platform to visualize deterioration risks on pipeline maps and manage remote reading data from smart meters. Analyzing data accumulated in the cloud enables an overarching view of daily operations and equipment information, contributing to faster on-site decision-making and more efficient management tasks.

Active use of digital technologies is beginning to fundamentally change how infrastructure maintenance is conducted. Field data from inspections and construction are sent to the cloud and shared instantly, and accumulated information is analyzed by AI to enable predictive maintenance. These initiatives are increasingly called “infrastructure DX” or “water DX,” and the Ministry of Land, Infrastructure, Transport and Tourism is supporting municipal adoption through issuance of technology catalogs and subsidy programs.

Innovation in Maintenance Models through Public–Private Partnerships (PPP/PFI/DBO, etc.)

Alongside technological renewal, efforts to explore new business schemes through public–private partnerships are progressing. As it becomes more difficult for governments alone to bear the burden of infrastructure maintenance, PPP (Public–Private Partnership) that leverages private capital and know-how is an important option.

Representative PPP approaches include PFI (Private Finance Initiative) and DBO (Design-Build-Operate). Under PFI, private companies undertake construction and operation, providing infrastructure using private finance and managing and operating it over a long term. DBO entrusts design, construction, and operation to the private sector in an integrated manner while public entities retain ownership and rely on private sector efficiency for operation. Both approaches aim to reduce costs and improve services by incorporating private-sector creativity and operational efficiency into public infrastructure projects.

There has been an increase in PPP cases in the water and sewer sector as well. For example, in sewage sludge treatment facilities, private operators commissioned under PFI/DBO schemes sometimes undertake facility improvement and integrated operations including biogas power generation and composting. Miyakonojo City in Miyazaki Prefecture and Kure City in Hiroshima Prefecture have set up proposal windows for PPP/PFI in sewer projects and actively solicit business proposals from the private sector. In the water sector, the 2018 revision of the Water Supply Act opened the door to concession models (transfer of the right to operate public facilities to private entities), and movements to grant operation rights of wide-area water services to private consortia have advanced in prefectures such as Miyagi and Osaka. This allows private capital to be injected for renovating aging facilities and enables operating companies to secure a wide range of technical personnel to maintain services.

Public–private collaboration also offers the benefit of leveraging private-sector cutting-edge technologies and know-how. In some PFI projects, contractors propose introducing AI for facility monitoring or adopting IoT devices and proactively promote DX within the contractual scope. Investments in advanced technologies that are difficult for the public sector to fund alone become feasible with private participation, ultimately contributing to longer infrastructure lifespans and improved services.

However, introducing PPP requires careful consideration of issues such as ensuring continuity of public services and risks of cost increases. The civil engineering and construction industry must work toward win–win collaboration so that both the public and private sectors can build sustainable maintenance models. The government is also advancing institutional reforms—such as the obligation to formulate management strategies and promotion of wide-area cooperation—and by advancing technological DX and institutional reform in parallel, comprehensive measures to address aging infrastructure are expected to accelerate.

Use of LRTK (Smartphone + High-Precision GNSS) for Simple Surveying

Among the latest technologies, surveying methods that combine smartphones and high-precision GNSS have attracted attention in recent years. The emergence of LRTK (low-cost RTK positioning technology) has made acquiring positional information for infrastructure management dramatically easier. RTK-GNSS is a technique that corrects satellite positioning errors in real time to achieve centimeter-level accuracy, but it traditionally required expensive dedicated equipment and specialized skill. LRTK enables high-precision positioning with a compact RTK-GNSS receiver that attaches to a smartphone for easy operation. Because it can be used by non-specialist surveyors and keeps implementation costs low, it is revolutionizing everyday on-site surveying.

In buried water and sewer infrastructure management, simple surveying using LRTK is useful in many situations. For example, precise position measurement of manholes and fire hydrants: traditionally, manhole positions recorded in sewer ledgers derived from aerial photogrammetry had errors of several tens of centimeters, but with LRTK measurement points can be obtained with errors within a few centimeters. This enables accurate pipeline layouts on digital maps and allows inspection and repair locations to be identified without confusion. When correcting pipeline routes or depths, high-precision coordinate data improves excavation planning accuracy, preventing accidents and shortening construction periods.

LRTK is also effective for as-built management and current-condition surveying. If as-built measurements at project completion can be completed using only a smartphone and a GNSS receiver, heavy machinery and large surveying teams can be substantially reduced. For instance, measuring road surface elevation and slope after excavation with LRTK and uploading the data to a cloud GIS database on-site eliminates the need to return to the office to produce drawings. In daily inspections, LRTK can instantly measure road subsidence in suspected sinkhole areas to determine urgency. Because it enables real-time, accurate positioning, additional measurements and corrections can be performed on-site, accelerating on-site decision-making.

Furthermore, LRTK is expected to help address personnel shortages. Because complex surveying skills are unnecessary, young staff or field workers can operate the system, and adequate-precision data can be acquired even when veteran surveyors are absent. As a result, field personnel can measure and record infrastructure conditions without relying on specialized surveying departments, improving efficiency and reducing dependency on individuals. Accumulated high-precision data can also serve as resources for future digital twin construction of infrastructure.

In this way, simple surveying with LRTK offers the values of “speed, low cost, and high accuracy” in many aspects of water and sewer infrastructure maintenance. As part of the DX in the civil engineering and construction industry, the image of field personnel completing necessary surveying with a smartphone in hand represents a transformative change to past conventions. Solving the problems posed by aging infrastructure requires a multifaceted approach, but wisely adopting new technologies like LRTK can reduce field burdens, enhance safety, and advance infrastructure asset management with an eye to the future.