Watch out for the hole – Why pipe leaks can cause sinkholes and land subsidence

On January 28 2025, 9 o'clock in the morning, a 5-meter-wide sinkhole suddenly ruptured the main road in Yashio, a city in Saitama Prefecture, northeast of Tokyo. A 74 year old driver fell into the hole a few seconds later with his mini truck. The truck was washed away into the sewage pipe and disappeared. Local fire squads and police came to the rescue of the old man after the incident.

To prevent sewage from spilling and flooding, authorities also called on about 1.2 million people in 12 surrounding towns to stop flushing toilets before finding the old man. Unfortunately, the sinkhole kept widening due to land subsidence, eventually forming a hole of 15-meter depth and over 40 meters in width. After 88 days, on May 3^rd, the driver was finally found downstream of the sewage.

The tragic incident had drawn the world’s attention to the aging sewage pipes in cities. The U.S. Geological Survey (USGS) estimates that sinkhole damage costs at least $300 million per year in the United States. In Japan, about 40% of the sinkholes were caused by broken gutters and storm drains.

From corrosion to collapse: How pipe deflection triggers ground instability

The health of sewage pipelines is important to cities. How does a sinkhole happen and what measures can be taken to prevent it?

It all starts underground, where invisible processes like corrosion, pipe deflection and soil erosion can quietly undermine infrastructure. If left unchecked, these issues can escalate into serious ground instability—sometimes with dramatic consequences.

Hydrogen sulfide (H₂S), commonly found in sewage systems, poses a serious threat to underground infrastructure. When this gas comes into contact with moisture on pipe walls, it forms sulfuric acid—a highly corrosive substance that gradually eats away at the pipe material. Over time, this corrosion can lead to cracks, leaks or even structural failure. Once a pipe is compromised, escaping water can begin to erode the surrounding soil, a process known as "piping." As soil particles are washed away, underground voids form, destabilizing the ground above. This can result in gradual subsidence—or in extreme cases, sudden sinkholes. Early detection and repair of pipe deflection are therefore critical to preventing costly and dangerous ground movement.

Proactive pipe rehabilitation: How Trelleborg helps prevent ground instability

Addressing pipe defects early is key to preventing land subsidence caused by pipe deflection and leakage. In many cities, aging sewer infrastructure poses a growing risk—not only to public safety but also to municipal budgets. Undetected cracks and leaks can lead to soil erosion and, ultimately, dangerous sinkholes. Regular inspection and timely rehabilitation of damaged pipes can prevent these issues before they escalate.

At Trelleborg, we specialize in trenchless pipe and sewer rehabilitation solutions designed to stop these problems at the source. For over a decade, we’ve partnered with contractors and infrastructure experts worldwide to deliver high-performance repair materials and equipment. Our solutions have helped restore pipeline integrity, protect communities and reduce long-term maintenance costs.

Talk to our pipe repair experts today to learn how we can support your next rehabilitation project.

Source:

[1] Japan truck found in pipe weeks after falling in sinkhole

https://www.bbc.com/news/articles/cdjd4z9d2ymo

[2] Japan sinkhole grows to almost Olympic pool length

https://www.arabnews.com/node/2588495/world

[3] How much does sinkhole damage cost each year in the United States?

https://www.usgs.gov/faqs/how-much-does-sinkhole-damage-cost-each-year-united-states

[4] Another Collapse in Saitama Pref. Road Connects Two Existing Sinkholes; Cause Apparently Was Sewer Pipe Corroded by Hydrogen Sulfide

https://japannews.yomiuri.co.jp/society/general-news/20250130-236158/

[5] The Toxic Effects of Hydrogen Sulfide (H2S) Gas From Sewers