Local Areas in Japan Inspect Sewage Systems Following Sinkhole in Saitama Pref.; Hole Thought to have Been Caused By Damaged Sewer Pipe

The Yomiuri Shimbun

15:23 JST, February 5, 2025

Local governments across the country have been conducting emergency inspections of sewage systems following the emergence of a sinkhole in Yashio, Saitama Prefecture.

The Land, Infrastructure, Transport and Tourism Ministry requested the inspections as the sinkhole, which trapped a truck and its driver, is believed to have been caused by a damaged sewer pipe.

A total of about 19 kilometers of sewage pipes managed by the Tokyo metropolitan government are set to be inspected. The pipes are laid in nine cities, including Higashi-Kurume and Kiyose.

In Higashi-Kurume on Tuesday, inspection work was carried out on a pipe that runs under a street and has an internal diameter of more than 3 meters. Two workers entered the pipe through a manhole and checked for cracks and other damage.

The Yokohama city government has also begun inspecting about 20 kilometers of its 12,000-kilometer sewage pipe network, covering areas where there is a high risk of hydrogen sulfide forming, causing deterioration. A detailed investigation will be conducted if any abnormalities are detected.

On Tuesday, workers opened a manhole cover on a road in Sagamihara, Kanagawa Prefecture, and descended into a sewage pipe that carries rainwater. A small camera was used to check for corrosion, damage and sediment buildup.

A city official said: “Sewer pipes continue to deteriorate. We want to maintain a safe and secure sewer system while incorporating new technology.”