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

Japan’s social infrastructure, developed during the high economic growth period, is aging one after another, and the burden of maintenance is increasing year by year. In particular, water and sewer infrastructure, which are essential lifelines supporting people’s lives, face challenges such as increased accident risk, rising maintenance costs, and personnel shortages. This article organizes the current status and issues of maintaining aging infrastructure for readers in the civil engineering and construction industry—such as municipal infrastructure managers, construction consultants, and engineers at small and large contractors—and introduces solutions using the latest technologies and public-private partnership models. At the end of the article, we also touch on how simple surveying using smartphones and high-precision GNSS receivers with LRTK can help water and sewer maintenance, and consider future prospects.

Current Status and Challenges of Maintaining Aging Water and Sewer Infrastructure

Across Japan, aging of water and sewer pipelines and treatment facilities is becoming serious. Many water and sewer systems were intensively developed in the 1960s and 1970s, so they are now reaching a simultaneous renewal phase. The proportion of pipelines that have exceeded their service life (statutory service life of about 40–50 years) is increasing year by year, reaching more than 20% of the total in the early 2020s. Aging pipes that have exceeded their service life are still in use, and over 20,000 leakage and breakage incidents occur nationwide each year, raising concerns about declining infrastructure reliability. Aging infrastructure can also exacerbate damage during large-scale disasters. In fact, the 2024 Noto Peninsula earthquake caused serious damage to water and sewer facilities and resulted in water outages for approximately 140,000 households. Given this situation, planned renewal and maintenance of aging infrastructure is an urgent issue.

Main challenges:

• Heavy burden of monitoring and inspection: Regular monitoring and inspection are indispensable to detect infrastructure deterioration early. However, traditional inspections rely heavily on visual inspection and sounding tests by human workers, making it difficult to check every nook and cranny of water and sewer pipes and facilities. For example, inspecting extensive pipeline networks requires many personnel and time, and sometimes night work or traffic restrictions are necessary to ensure worker safety. As a result, inspection frequency and scope are limited, increasing the risk of overlooking deterioration or delaying responses.

• Repair and renewal costs and fiscal burden: Repairs and renovations of aging infrastructure require enormous funds, but many municipalities do not have the financial leeway. With population decline and heightened water-saving awareness, water tariff revenues are declining while investment to renew aging facilities is increasing, worsening the balance of income and expenditure. A Ministry of Internal Affairs and Communications survey reported that about 12% of water service providers recorded operating deficits in fiscal 2022. At the current renewal pace, it is estimated that it would take more than 100 years to replace all water pipelines, and continuing with conventional methods may make infrastructure maintenance unsustainable.

• Shortage of technicians and skills transfer issues: On-site infrastructure maintenance faces serious problems with an aging and shrinking workforce. The number of staff engaged in water services peaked at about 80,000 in 1990 but fell to about 72,000 in the 2020s. Especially in small local utilities, new hiring is limited and veteran staff retiring at retirement age exacerbates labor shortages. The burden of balancing daily operations and massive equipment management with limited personnel is increasing, and the know-how of experienced workers becomes siloed and difficult to pass on. Traditional methods that rely on manpower have limits in efficiency, so DX (digital transformation) in maintenance and management is needed to reduce labor and standardize processes.

As described above, sites with aging infrastructure face a triple challenge of heavy inspection burdens, insufficient renewal funds, and shortage of personnel and technical capacity. To overcome these issues, the civil engineering and construction industry has recently been 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 sites. Technologies that once seemed like science fiction—AI, IoT, sensors, robots, drones, LiDAR, 3D models, and cloud integration—are being applied in practice, and automated inspections and predictive maintenance based on data utilization are becoming a reality. Below are the main advanced technologies useful for water and sewer maintenance and examples of their application.

Infrastructure condition monitoring using AI and IoT sensors

AI (artificial intelligence) and IoT (Internet of Things) technologies offer new possibilities for monitoring infrastructure condition and detecting anomalies. For example, in water pipe leakage detection, attempts have begun to use satellite data analyzed by AI to broadly identify leak locations that are invisible from the ground. By capturing moisture distribution with microwave data from the sky and having AI distinguish rainwater from leaks, it becomes possible to narrow down underground leakage areas more efficiently than before. Technologies have even emerged that can extract suspected leakage locations within an area about 200 m (656.2 ft) in diameter, which is expected to greatly reduce the effort required for wide-area leakage surveys.

AI is also used for deterioration prediction of distribution and sewer pipes. AI analyzes big data such as pipe burial age, material, and soil environment to predict how much each pipe has deteriorated and where the risk of failure is high. This allows prioritization of sections that need renewal in advance and helps plan systematic pipeline renewal. In practice, some municipalities have introduced systems that calculate water pipeline failure probability with AI and reflect it in renewal plan formulation. Because data-based decisions can determine where limited budgets should be invested for maximum effect, waste-free preventive maintenance becomes possible.

Moreover, real-time monitoring using IoT sensors is spreading. By installing network cameras, vibration sensors, and pressure sensors at facilities such as water purification plants and pump stations, equipment operation and abnormal vibrations can be monitored 24 hours a day. For example, NTT Group and Metawater have started proof-of-concept experiments to automate patrol inspections of water and sewer facilities, working to develop systems that automatically detect signs of abnormality by analyzing data from IoT sensors and cameras installed on site with AI. If realized, it would enable smart maintenance that allows remote facility condition monitoring and rapid response in case of abnormalities without personnel being constantly on site.

Inspection automation using robots and drones

In the realm of physical infrastructure inspection, the introduction of robot technology and drones (unmanned aerial vehicles) is advancing. These devices take on inspections in dangerous or confined spaces, improving safety and work efficiency.

Ground patrol robots and underwater robots: For inspections within water and sewer facilities, quadruped robots and underwater robots are attracting attention. For example, in wastewater treatment plants, quadruped patrol robots have been introduced to inspect equipment across vast facilities, and demonstrations have shown robots automatically collecting sensor readings from various devices so humans do not need to walk around. If robots can substitute in locations with poor footing or darkness, they can reduce worker burden and hazards. Similarly, attempts have been made to deploy underwater robot cameras inside sewer pipes to investigate internal cracks and sediment conditions. Narrow sewer pipes that previously required workers to descend through manholes can be inspected by robots without the risk of human injury.

Drone inspections: Drones excel at aerial and enclosed-space imaging, revolutionizing inspections of places humans couldn’t easily reach. For instance, inspections of aqueduct bridges spanning rivers and elevated water tanks can be performed with high-resolution cameras mounted on drones, obtaining imagery without scaffolding or aerial work platforms. The Kanagawa Prefectural Waterworks has introduced drones for inspecting bridges and reservoirs, establishing a system to check deterioration from various angles. This allows detection of fine corrosion and cracks that human inspectors might miss through image analysis, enabling early repairs.

Advanced cases of using small flying robots called spherical drones for internal inspection of sewer pipes have also appeared. In Himeji City, Hyogo Prefecture, a spherical drone approximately 40 cm (15.7 in) in diameter, “ELIOS3,” was deployed in 2025 for proof-of-concept autonomous flight and imaging inside conduits of aging sewers. Conventional human inspections of sewer pipes faced issues such as danger from toxic gases (hydrogen sulfide) and limited survey ranges because camera carts struggled to pass steps, but drones can fly over obstacles and capture images throughout the pipe interior. The results confirmed improved efficiency of initial diagnosis and enhanced safety, and full-scale use in regular inspections is expected going forward.

In this way, robot and drone technologies are enabling inspections in areas that are “inaccessible, out of sight, or dangerous,” achieving labor savings and higher-level inspection. Collected images and sensor data are accumulated in the cloud and analyzed by AI, leading to further efficiency improvements.

Data sharing via digital twins and cloud utilization

Centralized data management and remote information sharing are also crucial for infrastructure maintenance. Recently, digital twins of infrastructure—3D models that reproduce real structures in virtual space—are being developed using BIM/CIM and GIS. High-precision 3D data obtained by LiDAR (laser scanners) and photogrammetry are used to create detailed models of water and sewer facilities and terrain, and cases of managing these models in the cloud are increasing. For example, Kanda Town in Fukuoka Prefecture migrated water pipeline maps from paper to electronic maps and integrated plan views, photos, and inspection histories in the cloud, building a system that allows staff to share infrastructure information in real time. Plotting deterioration locations and repair histories on a digital map lets new personnel immediately understand past conditions, aiding planned maintenance.

There are also examples of remote monitoring and work support using cloud platforms. In Kawakita Town, Ishikawa Prefecture, various sensor values and equipment operation statuses at a water purification plant are visualized in a cloud monitoring system, with alerts sent to responsible personnel during abnormalities. This allows a small team to monitor multiple facilities and improves emergency response speed. Yokohama City Waterworks Bureau has also trialed remote work support using AR (augmented reality) smart glasses. On-site workers stream live video through smart glasses to veteran technicians at headquarters, who can check the scene in real time and send instructions via voice or AR markers, enabling the knowledge of experienced personnel to be shared remotely. This allows “one worker on site with multiple experts’ wisdom,” enabling labor savings without lowering the quality of complex work or problem-solving.

Private companies also offer cloud services for infrastructure management. For example, Mirait One Co., Ltd. provides a “Water DX Solution” that supports water and sewer utilities from survey and diagnosis to construction and maintenance. This service aggregates data collected by sensors and inspections into the company’s cloud platform, visualizes deterioration risk on pipeline maps, and manages remote reading data from smart meters. Analyzing data accumulated in the cloud enables an overview of daily operational status and equipment information, contributing to faster on-site decision-making and more efficient management operations.

Active use of digital technologies is starting to fundamentally change infrastructure maintenance. Field data from inspections and construction are sent and shared in the cloud immediately, and AI analyzes accumulated information to enable predictive maintenance; such cycles are gradually being realized. These initiatives are increasingly referred to as “infrastructure DX” or “water DX,” and the Ministry of Land, Infrastructure, Transport and Tourism is promoting municipal adoption through publication of technical catalogs and subsidy programs.

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

Alongside technological innovation, exploration of new business schemes through public-private partnerships is progressing. As it becomes difficult for governments alone to shoulder infrastructure maintenance, PPP (Public-Private Partnership) that leverages private capital and know-how is an important option.

Representative PPP methods include PFI (Private Finance Initiative) and DBO (Design Build Operate). Under the PFI model, private companies undertake construction and operation of facilities, using private capital for infrastructure development and providing long-term operation and management. The DBO model entrusts design, construction, and operation to the private sector as a package, while the public sector retains ownership and delegates efficient private operation. Both aim to introduce private creativity and managerial efficiency into public projects to reduce costs and improve services.

In the water and sewer sector, adoption of these PPP methods has increased. For example, in sludge treatment facilities at sewage plants, private operators under PFI/DBO contracts sometimes handle everything from equipment provisioning to biogas power generation and fertilizer production in an integrated operation. Cities such as Miyakonojo in Miyazaki Prefecture and Kure in Hiroshima Prefecture have established proposal windows for PPP/PFI in sewerage projects and actively solicit proposals from the private sector. In the water sector, the 2018 revision of the Water Supply Act lifted restrictions on the concession method (transfer of operational rights of public facilities to the private sector), and moves to grant operation rights of wide-area water supplies to private consortia have advanced in Miyagi Prefecture, Osaka Prefecture, and elsewhere. Through private capital injection, it is expected that private consortia can advance renovation of aging facilities and that operating companies can secure a wide range of specialized engineers to maintain service quality.

PPP also offers the advantage of leveraging private-sector cutting-edge technologies and know-how. For instance, in PFI projects, contractors may propose AI-based facility monitoring or IoT device adoption and actively promote DX within the contract scope. Advanced technological investments that are difficult for governments alone to fund can 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 the risk of cost increases. The civil engineering and construction industry must aim for sustainable maintenance models where public and private sectors collaborate in a win-win relationship. The government is also advancing institutional reforms such as mandating management strategy formulation and promoting wide-area cooperation; moving forward, combining technological DX and institutional reform as twin approaches will accelerate comprehensive measures against aging infrastructure problems.

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

Among the latest technologies, surveying methods that combine smartphones and high-precision GNSS receivers have attracted attention in recent years. The emergence of LRTK, a low-cost RTK positioning technology, has made acquiring positional information for infrastructure management dramatically easier. RTK-GNSS is a technology that corrects satellite positioning errors in real time to achieve centimeter-level positioning accuracy (half-inch accuracy), but traditionally required expensive dedicated equipment and specialized skills. With LRTK, a compact RTK-GNSS receiver that fits in a pocket is attached to a smartphone, enabling high-precision positioning with simple operation. Because it can be handled without a licensed surveyor and keeps introduction costs low, it is revolutionizing routine on-site surveying.

In buried water and sewer infrastructure management, simple surveying with LRTK is useful in many situations. For example, it enables precise location measurement of manholes and fire hydrants. Traditionally, manhole positions recorded in sewer ledgers had errors on the order of several tens of cm (several in) from aerial photogrammetry, but using LRTK can yield measurement points with errors within a few cm (within a few in). This allows accurate pipeline layouts on digital maps and makes it easy to locate inspection and repair sites. When correcting buried pipe routes or depths, having high-precision coordinate data improves excavation planning accuracy, helping prevent accidents and shorten construction periods.

LRTK is also effective for as-built management and as-built surveys. At the completion of water and sewer construction, if the finished shape of the work site can be measured and recorded using only a smartphone and GNSS receiver, the need for heavy survey equipment and personnel can be greatly reduced. For example, measuring road surface height 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 create drawings. In routine inspections, LRTK enables immediate measurement of road subsidence at suspected collapse points to assess urgency. Because it provides real-time accurate positioning, additional measurements or corrections can be made on site while checking the data, speeding up on-site decision-making.

Furthermore, LRTK use is expected to help address personnel shortages. Because specialized surveying skills are not required, young staff and workers can handle it easily, and sufficient-precision data can be obtained on sites without veteran surveyors. As a result, on-site personnel can measure and record infrastructure conditions themselves without relying on a dedicated surveying department, improving efficiency and reducing dependence on specific individuals. Accumulated high-precision data can also serve as resources for building digital twins of infrastructure in the future.

Thus, simple surveying using LRTK provides the value of “speed, low cost, and high precision” in various aspects of water and sewer infrastructure maintenance. As part of DX in the civil engineering and construction industry, the ability to complete necessary surveying on site with a smartphone in hand is a transformative change that overturns conventional wisdom. Solving the challenges of aging infrastructure requires a multifaceted approach, but smart adoption of new technologies like LRTK can realize reduced on-site burdens, improved safety, and advanced infrastructure asset management with an eye to the future.