Neglected Corroded Water Pipes: Shocking Photos Reveal the Hidden Danger

Changes in water infrastructure

“This is the inside of a water pipe that has been in use for around 40 years. Originally, it was a clean, hollow space, but over time, scale and impurities have accumulated massively, leading to corrosion. If left unchecked, this can result in water leaks or pipe breakages, which could lead to major accidents.”

With a sigh, Mr. A, who runs a water distribution pipe maintenance business in Osaka City, shared his concerns.

Japan’s water infrastructure is facing serious issues. On January 28, a road in Yashio City, Saitama Prefecture, suddenly collapsed. A 2-ton truck driven by a 74-year-old man fell into a hole about 10 meters in diameter and 5 meters deep. The suspected cause of the collapse was damage and water leakage from a sewage pipe.

About two weeks after this accident, water pipes burst in quick succession in Sakai-ku and Mihara-ku, Sakai City, Osaka Prefecture, causing water outages and road closures.

A former employee of the Osaka City Waterworks Bureau, Mr. B, emphasized the severity of the situation.

“The lifespan of water pipes is generally considered to be around 40 to 50 years. Ideally, they should be replaced before exceeding their lifespan. However, many of Osaka’s water pipes have aged, corroded, and been left in a deteriorated state.”

Mr. B pointed to the decreasing length of newly replaced distribution pipes as an indicator of Osaka City’s dire situation.

“In order to properly maintain the infrastructure, about 70 to 80 kilometers of new water pipes need to be installed each year. Up until about a decade ago, this pace was maintained. However, in recent years, the installation rate has dropped to around 40 to 60 kilometers. According to the ‘FY2023 Osaka City Water Business Accounting Report,’ the total installation distance was approximately 45 kilometers—nearly half of what it should be. This means that many deteriorating pipes remain in place.”

The severity of the situation is not just reflected in installation distances. Mr. A lamented that the number of construction projects itself is also decreasing.

“For example, in fiscal year 2019, Osaka City commissioned about 90 water pipe installation projects to private contractors. However, the number has steadily declined, dropping to 62 in fiscal year 2023. Among contractors and water bureau employees, there are whispers that the budget is being diverted to construction projects for the Osaka-Kansai Expo. Some contractors are struggling financially due to the reduced number of projects.”

What if the Nankai trough earthquake strikes now?

A raised the alarm by drawing on his own disaster experience.

“During the Great Hanshin-Awaji Earthquake, water pipe damage delayed firefighting efforts, leading to catastrophic losses. Aging water pipes, as well as those failing to meet seismic standards, should be replaced as soon as possible. If the Nankai Trough Earthquake were to strike now, firefighting efforts would be severely hampered, and Osaka could be engulfed in flames.”

Why has the total pipe replacement distance decreased? The Osaka City Waterworks Bureau’s Engineering Department responded:

“We prioritize replacing ordinary and high-grade cast iron pipes, which have deteriorated the most over time and suffered high damage rates in past earthquakes. In particular, we are accelerating the renewal of large-diameter main pipelines. For smaller-diameter distribution pipes, we have calculated future replacement needs based on past surveys and set an immediate renewal pace of approximately 45 km per year. Moving forward, we plan to increase this to an annual average of 53 km in total pipeline updates.”

However, A countered, stating, “53 km of updates is nowhere near enough.”

Yoshiharu Yokoyama, director of the Daichi Disaster Risk Research Institute, also weighed in:

“The sinkhole accident in Yashio City occurred in an area with soft ground. When the ground is weak, damage to sewer pipes can cause soil to wash into the pipes, creating cavities under roads. This weakens the ground, making it unable to support the weight and vibrations from vehicles, ultimately leading to sinkholes. Osaka has many reclaimed land areas, and in the past, the sea extended far inland, resulting in widespread weak ground conditions. The Expo site itself is built on reclaimed land. Compared to other prefectures, Osaka must take even greater precautions against aging water pipes.”

How will Mayor Hideyuki Yokoyama (43) and Governor Hirofumi Yoshimura (49) respond to these urgent warnings from those on the ground?

From the March 7, 2025, issue of “FRIDAY”