At least 200 households in Ruiru, downstream of Kijabe, have been instructed to vacate their homes by 6 p.m. on Tuesday as water levels near the railways continues to rise.
According to the Interior Ministry, 86 families have already heeded the warning and relocated to government-designated safe regions.
According to CS Kithure Kindiki, those not following instructions must depart for public safety.
Flash floods in Mai Mahiu last week killed at least 71 people and left 51 missing.
Water washed away many residences in the early hours of last Monday, triggering emergency reactions from the national and county administrations, who have been camping at the site for the last 24 hours.
In a message to newsrooms, Water Cabinet Secretary (CS) Zechariah Njeru stated the tragedy was caused by a clogged railway line tunnel prevented appropriate water flow via the River Tongi.
"The channel got blocked due to debris, stones, trees and soil brought about by the heavy downpour in the area thereby preventing water flowing through the River Tongi course and its small tributaries to move downstream," said Njeru.
He noted that the river and its tributaries broke their banks under tremendous pressure, sweeping the railway line and flowing downstream.
Njeru further explained that the location does not have a dam, as claimed in some stories, and that the only dam in the area is Matches Dam, located upstream and far from the impacted premises.
