South Korea's public sewage plants exceed capacity 50–60 times a year, data shows

A significant number of South Korea's public sewage treatment facilities are chronically overloaded, newly released government data shows.

Democratic Party of Korea lawmaker Kim Ju-young, a member of the National Assembly's Climate, Energy, Environment and Labor Committee, compiled data submitted by seven regional and local environmental agencies nationwide. The figures show that public sewage treatment facilities exceeded 100 percent capacity a total of 334 times over the six-year period from 2021 through June 2026.

The annual breakdown shows 61 cases in 2021, 52 in 2022, 65 in 2023, 62 in 2024 and 57 in 2025 — consistently 50 or more overload incidents each year. This year, 37 cases were recorded in the first half alone.

By regional agency, the Han River Basin Environmental Office logged the most cases over the six-year period with 116, followed by the Geum River Basin Environmental Office with 70, the Daegu Regional Environmental Office with 38, the Yeongsan River Basin Environmental Office and the North Jeolla Province Regional Environmental Office with 31 each, the Nakdong River Basin Environmental Office with 30, and the Wonju Regional Environmental Office with 18.

Of those cases, 53 involved severe overloads where capacity utilization exceeded 120 percent. Eighteen facilities were found to have been operating above capacity for six consecutive years.

The Geochang Sewage Treatment Plant, which ran at 171.3 percent capacity in 2021, recorded rates of 160.3 percent in 2022, 133.4 percent in 2023, 131.9 percent in 2024 and 124.9 percent in 2025 — exceeding 120 percent for five straight years. The facility's utilization rate stood at 117.0 percent in the first half of this year.

The main causes of overloading include the influx of unaccounted water — such as rainwater and groundwater — as well as increased sewage volumes driven by urban development and population changes.

Prolonged overloading can degrade facility efficiency, and during heavy rainfall, inadequately treated sewage may flow into rivers and streams, raising the risk of water pollution.

"Sewage treatment is directly tied not only to public health and safety but also to water quality, making repeated government-level inspections essential," Kim said. "Separate management measures must be drawn up for overloaded facilities, and concrete steps — including repairs to aging pipelines and facility scale-ups — must be put in place without delay."