Seoul to complete overhaul of aging water pipes by 2028

The Seoul Metropolitan Government has launched a project to overhaul water mains that have been in use for more than 30 years, targeting a total of 3,074 kilometers for replacement and repair by 2028.

The city classifies pipes buried for more than 30 years as long-term-use mains due to concerns over turbid water, leaks and ground instability, and prioritizes repairs based on data analysis including deterioration assessments and leak histories, officials said Friday. Since 2020, the city has completed work on 364 km of pipe, leaving approximately 2,710 km still to be addressed.

Deteriorated water mains are among the causes of ground subsidence. The overhaul is intended to prevent leaks and stop foreign matter from entering the water supply.

Pipes are selected for repair through a combined assessment of deterioration — factoring in installation age, burial depth and soil corrosiveness — and data analysis covering leak records over the past 20 years and proximity to major construction sites and subway stations.

The city plans to complete repairs on 111 km of vulnerable pipes — identified through advance procedures including traffic management planning — by the end of this year. Work on 33.7 km has already been finished, and the project is proceeding on schedule.

Given the risk that long-term-use mains could cause ground subsidence through leaks, the city plans to invest 727.1 billion won ($482 million) through 2028 in intensive repairs of leak-prone pipes, strengthening the stability of water supply facilities and ensuring a reliable supply of tap water.

Given the large budget the project requires, the city is pursuing designation as a nationally funded project to secure financing, while also conducting on-site inspections and safety management around construction zones to prevent accidents.

"The water main repair project is a core infrastructure investment that not only ensures a stable supply of clean tap water to residents but also protects public safety by preventing sinkholes and other accidents," said Kwon Min, head of the Seoul Arisu Headquarters. "We will do our utmost to meet our annual repair targets without delay so that residents can use Arisu water with greater peace of mind."