The total length of sewer pipes in Japan that have so far been found to need rapid action stands at about 300 kilometers, a survey by the infrastructure ministry showed Wednesday.

The ministry will ask municipalities that manage such sewer pipes to take necessary steps early. It plans to provide them with financial and technical support.

The nationwide survey of sewer pipes that have been in place for 30 years or more was conducted by visual inspections and using drones after a sinkhole accident swallowed up a truck in January in the city of Yashio in Saitama Prefecture.

In March, the ministry required local governments to examine within a year a total of 5,000 kilometers of sewer pipes with a diameter of 2 meters or more, in order to understand their levels of corrosion, sagging and damage. It aimed by summer to complete with priority the survey for some 813 kilometers of pipes in total, covering those with a similar structure to that at the Yashio site, in 43 prefectures.

As of August, the survey had been finished for some 621 kilometers of pipes. The ministry concluded that 72 kilometers in 35 prefectures required rapid measures within a year in principle. It found that action had to be taken within five years after initial repair for some 225 kilometers in 36 prefectures.

The ministry has asked local governments to report survey results for sections of sewer pipes other than those with priority by the end of February 2026.