Expert Says Bangkok Floods Are Drainage, Not the River

Last Updated on September 27, 2026 by Jeff Tomas

BANGKOK – Heavy rains continue to drench the city, leaving many streets under standing water this week. Residents often blame the major rivers, but experts say the real problem is much closer to home. The primary cause of the current flooding is simply a lack of local drainage capacity. City pipes cannot handle the massive volume of daily rainfall pouring down right now.

Water expert Chawalit Chantararat explains that intense downpours are simply overwhelming the city’s drainage network. Prolonged heavy rain easily exceeds the normal limits of major water tunnels and connecting local canals. Excess water collects on the main roads because it cannot be flushed away fast enough. The floodwater simply cannot reach the sea before the next heavy storm hits the city.

Key Takeaways

Intense rainfall of 100–150mm is overloading Bangkok’s local drainage network.
The Chao Phraya River remains 40cm below its banks at key monitoring stations.
Standing water on roads could reach depths of up to 50cm in low-lying areas.

Chawalit pointed out that the mighty Chao Phraya River is not the immediate threat today. Monitoring stations show the river remains roughly 40 centimeters below its banks right now. These lower river levels were recorded near the Nuan Chawee Bridge and the Samsen premises. This confirms that northern runoff is not flooding the capital city at this current time.

Instead, daily rainfall totals hitting up to 150 millimeters are straining our local canals. High canal water levels restrict the flow of runoff from city streets into the main system. This bottleneck leaves shallow water pooling across local roads and low-lying residential neighborhoods across the city. Experts expect this slow-moving standing water to persist through the very end of the weekend.

Poor Drainage, Not River Water

A recent report on flooding in Bangkok noted that these drainage issues might cause major travel disruptions. Flooding in these low-lying zones usually develops slowly rather than arriving as a sudden flash flood. This gradual rise gives residents enough time to monitor conditions and move cars to higher ground. People should prepare for expected water depths between 10 and 20 centimeters on main roads.

Some especially low spots could see floodwater levels reach up to 50 centimeters deep. City officials are closely watching several main waterways, including the Lat Phrao and Saen Saep canals. These critical canals are currently near their limits and threaten to spill over their banks soon. Residents living right next to these canals should stay alert for sudden and unexpected water rises.

City teams are working around the clock to pump the extra water out of drainage tunnels. However, continuous heavy rain makes it difficult to clear the main streets in a timely manner. Everyone hopes for a clear break in the weather to give the water pumps a chance. Until the rain stops, daily commuters will need to deal with major traffic delays and puddles.

If you live in a low-lying community, check your local news for fast weather updates. Make sure your most important items are safe and kept well above the ground floor. Slow-flushing toilets in your home might also be an early sign of neighborhood drainage trouble. Stay safe on the wet roads and avoid driving through deep water whenever it is possible.