Officials said the dam water and mud spewed out of the reservoir and submerged homes over a radius of nearly 2 kilometers.
Interior Cabinet Secretary Fred Matiangi was set to visit the site Thursday.
At least 132 people have died since March from floods caused by seasonal rains, Kenya's government said Wednesday.
The deaths from the dam burst raise the death toll to nearly 170 people. At least 225,436 people have been displaced from their homes, according to a government statement.
Military helicopters and personnel have for the past week been deployed to rescue people marooned by the flooding.
The floods hit as this East African nation was recovering from a severe drought that had affected half of the country.