Four bodies were retrieved from River Athi on Friday morning, raising the number of those who have died after heavy rains to at least 13.
The four who died while attempting to cross the swollen river on Thursday night.
Matungulu OCPD Samuel Mukuusi said the bodies were found at Joska-Kamulu bridge.
The identities of the victims were yet to be established.
Nine people died in massive destruction caused by torrential rains that continued to pound many parts of the country yesterday.
Six people died in Mwingi, two in Kajiado and one student in Mai Mahiu, Naivasha, as several roads were cut-off and cars submerged in floodwater.
Mto wa Mawe River in Athi River, Machakos County, burst its banks on Thursday, rendering a section of Mombasa Road impassable.
The road was reopened on Friday morning KeNHA's Assistant Director of Corporate Affairs saying repairs were underway.
Meanwhile, some residents of the nearby Green Park Gardens Estate have accused Machakos Governor Alfred Mutua of taking advantage of their plight to play public relations for political gain.
More on this: Nine dead, chaos as heavy rains strike