Authorities say the downpour triggered flash floods that swept through residential neighbourhoods, leaving a trail of destruction and disrupting normal life across the capital.
Police officials confirmed that the deaths occurred in different areas of the city that were badly affected by the rising waters.
Rescue teams have been moving through flooded neighbourhoods since early morning, searching for survivors and helping residents who were trapped in their homes.
Among the worst-hit areas is Mukuru, where floodwaters reportedly rushed through homes built along drainage paths and riverbanks.
Many residents in the settlement woke up to find water flowing into their houses, forcing them to flee to safer ground.
Another heavily affected neighbourhood is Kibra, one of the city’s largest informal settlements.
Residents there reported that the rains began late at night and continued for hours, causing water levels to rise quickly in low-lying sections.
Flooding was also reported in Mathare and Huruma, where narrow roads and poor drainage made it difficult for water to flow away.
In some places, people were forced to move their belongings to higher ground as water entered homes and small businesses.
Other affected areas include South B and South C, where several roads were temporarily impassable due to flooding.
In Pipeline, residents reported that floodwaters moved rapidly through streets and residential blocks during the night.
Police also reported flooding incidents in Roysambu, Kahawa West and Githurai.
In some of these areas, vehicles stalled on flooded roads while residents struggled to move through waterlogged streets.
Parts of Westlands were also affected, with floodwaters disrupting traffic and business activities early in the morning.
Several roads experienced heavy congestion as drivers tried to navigate through flooded sections.
Emergency teams from the police, county government and humanitarian organisations have been deployed to assist affected communities.
Their work includes rescuing trapped residents, evacuating families from risky areas and assessing the damage caused by the floods.
Authorities say the search for missing persons is still ongoing in some neighbourhoods, and the number of casualties could change as rescue teams continue their operations.