More rain is forecast for the Bangkok area throughout this week, with flooding expected in Ang Thong and Ayutthaya provinces.
The Meteorological Department on Monday forecast rain for more than half of Greater Bangkok this week, with heavy falls due on Sunday.
The Disaster Prevention and Mitigation Department warned of floods in part of Ang Thong and most areas of neighbouring Ayutthaya over the next 24 hours.
The Chao Phraya River flow was measured at 1,498 cubic metres per second on Monday, according to the institute.
The Royal Irrigation Department has said the water at this rate is still manageable. The Chao Phraya barrage dam released 2,700 m3/s during the great flood of 2011.
Meanwhile, former super typhoon Yagi has been downgraded to a low pressure system after causing death and havoc in the Philippines, Vietnam and southern China.