On Monday, the authorities raced to evacuate and support hundreds of people trapped in their homes.
The Ndjili River, which cuts through the city of around 17 million people, overflowed its banks on Friday night, submerging hundreds of buildings.
Officials said most of the fatalities were caused by walls that collapsed shortly after the deluge began.
While the situation had improved by Monday morning, some access roads remained blocked and traffic was limited.
Many residents blamed the government for not responding quickly enough to the disaster.
“I was born, grew up, and had my children here in Congo. I have never encountered these kinds of situations,” said François Munday. “The country is not working.”
The government has set up at least four emergency shelters for hundreds of displaced families, and many across the city are without water after infrastructure was damaged
Françoise Mutela sells bananas and okra in the city, and was stopped on her way to her usual spot by the floodwaters.
“I have never seen something like this before,” she said.
With many having lost everything, and homes, buildings, and infrastructure damaged or destroyed, it is unclear how long it will take the city to recover.
The disaster comes at a difficult time for the DRC which is battling M23 rebels in the east of the country, intensifying a humanitarian crisis there.