Water situation updated as agency warns 8 eastern provinces of floods

The Office of the National Water Resources (ONWR) has warned of flooding and flash floods in eight eastern Thai provinces during September 22–27, 2026, with Sa Kaeo recording the country’s highest reported accumulated rainfall at 211mm.

The September 25 update identified eastern Thailand as the region facing the greatest flood risk, based on accumulated rainfall and flooding data. Many parts of the country continued to experience heavy to very heavy rain.

ONWR is also monitoring the Chao Phraya basin and reservoirs nationwide ahead of further heavy rain on September 26–27.
 

Sa Kaeo tops reported rainfall totals at 211mm

Sa Kaeo recorded the highest rainfall total in ONWR’s update, followed by Buri Ram with 156mm. The reported regional maxima were:

• Eastern Region: Sa Kaeo Province, maximum rainfall of 211 millimeters (highest in the country)
• Northeastern Region: Buri Ram Province, maximum rainfall of 156 millimeters
• Central Region: Phra Nakhon Si Ayutthaya Province, maximum rainfall of 139 millimeters
• Northern Region: Nakhon Sawan Province, maximum rainfall of 106 millimeters
• Southern Region: Narathiwat Province, maximum rainfall of 94 millimeters
• Western Region: Phetchaburi Province, maximum rainfall of 83 millimeters

Eight eastern provinces under flood watch until September 27

ONWR’s heightened flood watch for September 22–27 covers the following eight provinces and districts:

1. Sa Kaeo: Mueang Sa Kaeo and Watthana Nakhon.
2. Prachin Buri: Mueang Prachin Buri, Na Di, Kabin Buri and Prachantakham.
3. Nakhon Nayok: Pak Phli, Ban Na and Mueang Nakhon Nayok.
4. Chachoengsao: Sanam Chai Khet and Tha Takiap.
5. Chonburi: Bo Thong, Si Racha, Bang Lamung, Nong Yai and Sattahip.
6. Rayong: Mueang Rayong, Khao Chamao and Ban Khai.
7. Chanthaburi: Makham, Tha Mai, Kaeng Hang Maeo, Pong Nam Ron, Khlung and Khao Khitchakut.
8. Trat: Mueang Trat, Khao Saming, Khlong Yai and Bo Rai.

Trat had already experienced flash flooding in Bo Rai and Khao Saming after an earlier downpour delivered 140mm of rain in five hours.
 

Chum Saeng water levels rise under Chao Phraya watch

ONWR reported rising water levels at station N.67 in Chum Saeng district, Nakhon Sawan, although the river remained below bank level. Water levels at station P.17 in Banphot Phisai district were declining.

The Chao Phraya basin update provided the following readings:

• Station C.2, Mueang Nakhon Sawan: River flow was 1,795 cubic metres per second. The water level stood at 22.17 metres above mean sea level, or 3.53 metres below the riverbank.
• Chao Phraya Dam: Discharge remained at 1,750 cubic metres per second. Water levels upstream and downstream stood at 16.71 metres and 13.89 metres above mean sea level respectively.
• Station N.67, Chum Saeng: The water level stood at 26.09 metres above mean sea level, or 2.12 metres below the riverbank, with an upward trend.

Flood-risk households advised to prepare for sudden flooding

Residents in the eight eastern provinces and low-lying riverside communities are advised to take the following precautions:

• Move belongings higher: Relocate possessions, electrical appliances and vehicles to higher ground.
• Follow official warnings: Monitor announcements from ONWR and the Thai Meteorological Department closely.
• Prepare emergency supplies: Set aside non-perishable food, drinking water, medicines and torches.
• Take electrical precautions: If water starts entering the home, switch off the mains electricity only if it is safe to do so.