Mass Transit Authority Investigates Water Leak in Purple Line Tunnel
MRTA confirms water seepage in Purple Line tunnel extension near Sai Yai poses no structural risk, with contractors working to stop the leak from a sump pit 30 meters underground.
The Mass Transit Organization of Thailand (MRTA) has inspected water seepage into an underground tunnel section of the Purple Line extension near the Sai Yai intersection, confirming no structural subsidence in the tunnel or adjacent buildings while maintaining continuous safety monitoring.
The water seepage incident occurred in a sump pit approximately 30 meters below ground level in the construction area of the Purple Line extension project (Lime Kiln to Rat Burana section, Kaen Kanachanaphisek Ring Road), Contract 4 (Phra Phuttha Bridge to Dao Kha Nong section) on July 8, 2025.
As of July 9, 2025, the MRTA clarified that water seepage is preliminary suspected to originate from the sump pit joint and poses no impact to tunnel structural integrity. The Contract 4 construction contractor is expediting ground improvement work to halt seepage while maintaining strict engineering control of water infiltration. The current water leakage volume is manageable, with no effects on road or building subsidence. The MRTA has instructed construction supervisors PMCSC2 and the Contract 4 contractor to continuously inspect and monitor the stability and safety of adjacent structures.
On the evening of July 8 at 11:00 PM, Prime Minister Anutin Charnvirakul, Deputy Prime Minister Pipat Ratchakitprakarn, and Transport Minister's deputies, along with representatives from the Department of Disaster Prevention and Mitigation and police, conducted on-site monitoring. The Prime Minister ordered the MRTA to enhance safety surveillance of adjacent buildings to assure public confidence and safety, with emergency response plans prepared.
