BTS Tackles Water Leak Issues in Purple Line South Tunnel

On July 10, 2025, Montri Dethaskulsom, chairman of the Bangkok Mass Transit System (BTS), along with BTS Governor Kajphachai Udomtammarakdi and Assistant Governor Kitti Ekwallop, visited the Purple Line South tunnel to monitor the situation. They confirmed that the area is actively addressing water and sand seepage problems using engineering techniques. The faster the seepage can be reduced, the sooner ground and road surface movement will stabilize. The Purple Line South underground railway construction is now over 70 percent complete, with contract 4 nearly finished and expected to conclude this month. Contract 3 remains, with the first boring machine currently at Samyod Station and the second at the Constitutional Court. The overall project is expected to be completed by October 2025. Earlier this week, water seepage was discovered inside the tunnel. Contractors attempted repairs, but the high water pressure of approximately 20 meters at the incident site prevented effective sealing, causing tunnel flooding. Staff currently pump water out at 50 cubic meters per hour to maintain water levels, as draining it completely would allow external water to surge inward. Continuous rainfall may be complicating work due to groundwater issues. BTS and the contractor coordinated with Bangkok authorities to provide temporary accommodation and cover expenses for affected residents. A coordination center has been established at the incident site to assist residents. The underground Samsen Station project, which faced earlier problems, is also expected to reopen by late 2025. BTS emphasized it strictly follows construction procedures and halts work to repair any seepage issues before proceeding. No quality construction problems have been reported previously, though the true cause of this incident requires further investigation.