The Patenga Met Office has recorded 235 mm rainfall in the last 24 hours only in Chittagong.
Met Office official Farid Uddin told bdnews24.com that the rain is likely to continue for another day.
He said the maritime ports have been advised to show cautionary signal number 3 due to the stormy weather in the Bay of Bengal.
Many busy roads and areas in Chittagong, including Sholoshahor, Muradpur, Mohammadpur, Chandgao, Chawkbazar, Agrabad, Halishahor, Patenga, Bakoli and Kathgorh, have gone under waist-high water due to heavy showers that started on Thursday night.
Bandarban flood woes continue
Floods have affected at least 1,800 families in Bandarban Sadar, Lama and Naikkhangchharhi Upazilas, district authorities and locals said Sunday morning.
Road links were snapped due to the incessant rain over the last four days. The downpour caused many landslides but there were no casualties.
Bandarban Sadar UNO Md Shafiqul Islam said they have arranged for relief materials including food for those seeking refuge at the shelters set up in all primary schools.
The Upazila officer added that a special army medical team was on standby for emergencies.