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Sinkhole fears deepen as budget shortfall hinders repair of aging pipes in Seoul

Published: 09 Oct. 2025, 15:47

District officials and safety personnel conduct a recovery effort to fill up a sinkhole that appeared in Mapo District in western Seoul in April. [NEWS1]

A third of Seoul’s aging sewage pipes in urgent need of repair remain untouched due to a budget shortfall, raising concerns about sinkhole risks across the city.

Of the 124 kilometers (77 miles) of aging sewage pipes in Seoul that require immediate repair to prevent sinkholes and other accidents, 45 kilometers — or 36 percent — remain untouched due to a lack of funding, according to the city government on Thursday.

Seoul has a total of 10,866 kilometers of sewage pipelines. Of that, over half — 6,029 kilometers, or 55.5 percent — are more than 30 years old. If damaged, these outdated pipes can cause the ground to collapse, as water leaking from cracks can erode the soil, creating voids underground.

In fact, 51 of the 122 sinkhole incidents reported in the past five years — or 42 percent — were caused by damaged sewage lines, according to the city government. In response, Seoul identified 124 kilometers of high-risk areas for urgent repair by inspecting locations where sinkholes had occurred and where pipes were over 30 years old.

However, only 79 kilometers of that critical infrastructure will be repaired this year. The remaining 45 kilometers are on hold due to a budget shortfall. The total cost for repairing all 124 kilometers is estimated at 186 billion won ($131 million). However, even with 98.7 billion won in city funding and a one-time 33.8 billion won subsidy from the central government, the available budget amounts to only 132.5 billion won, leaving a gap of 53.5 billion won.

A massive sinkhole is seen near an intersection in Gangdong District in eastern Seoul on March 25. The sinkhole appeared a day before and injured one vehicle passenger and killed another motorcyclist. [NEWS1]

“We will begin repairs on the remaining 45 kilometers as soon as additional funds are secured,” said an official from the Seoul Water Circulation and Safety Office.

Due to its dense population and long urban history, Seoul has undergone more frequent sewer construction than other metropolitan cities, resulting in its sewage infrastructure aging more rapidly. In Seoul, 66.1 percent of sewage lines are over 20 years old, compared to an average of 56.2 percent in Korea’s six other major cities, including Busan and Daegu.

Moreover, around 150 kilometers of sewer lines in Seoul reach the 30-year threshold each year, but only 100 kilometers — or 66.7 percent — are being repaired annually.

A large sinkhole measuring 5 meters (16 feet) long and 1 meter wide opens on a road in Sasang District, Busan on Aug. 12. [YONHAP]

Seoul is currently the only one of Korea’s 17 metropolitan and provincial governments that does not receive consistent national funding for sewer maintenance. The recent 33.8 billion won in government support was a one-off measure following sinkhole accidents in Yeonhui-dong, Seodaemun District, western Seoul, and Myeongil-dong, Gangdong District, eastern Seoul.

“With the number of aging pipes growing every year, it's becoming increasingly difficult for the city to manage repairs using its own budget,” said Jeong Seong-guk, head of the Seoul Water Circulation and Safety Office. “The criteria for national funding should be revised to focus on risk factors such as the length of aging pipes, history of ground subsidence, and density of underground infrastructure, rather than relying solely on fiscal independence.”

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY KIM MIN-WOOK [[email protected]]