K-Water completed the Daesan seawater desalination plant in Seosan on December 18, 2025. It desalinates 100,000 tonnes a day of seawater for industrial use by reverse osmosis, at a reported total project cost of KRW 317.5 billion.
The 2012 warning
The plant answers a failure that came close. In 2012 the Daeho reservoir, the Daesan industrial area's water source, fell to single-digit storage and factory operations nearly stopped. Full operation of the new plant was planned from 2026.
Droughts outside the big dams
Korea's national storage is large. In 2022 the ministry managed 34 dams, 20 of them multipurpose. But shortages have hit places that depend on local supplies. On June 13, 2022, 5,558 households, or 11,916 people, in 10 municipalities not served by multipurpose dams were receiving hauled water. On September 20, 2025, Gangneung's Obong Reservoir stood at 44.9% against a seasonal norm of 72.4%, a day after time-based supply limits on 113 apartment complexes were lifted.
More supply without new reservoirs
The national plan has moved away from new storage. Of 14 proposed climate-response dams, 5 remain under study after the August 27, 2026 review. The largest new supply source is conveyance: Yongin phase 1 will carry 310,000 tonnes a day from Paldang Dam over about 47 km, with supply planned from May 2029.
The funding question
The bulk business that pays for this recovered only 78.1% of its cost in 2025. The treated-water tariff of KRW 432.8 per m³ has not changed since September 23, 2016.
Which parts of Korea's water system are most exposed, which institutions hold each layer, and where the main opportunities lie to 2030 are set out in the full analysis. The full report, Water Systems Overview: K-Water, is available for USD 499. For a free overview, read the K-Water Utility Snapshot.