Thrill-seekers risk will be arrested if they swim at the Sagana Falls in Muruguru, Nyeri County, a government official has said.
The announcement followed an incident last Thursday, when a student of Dedan Kimathi University of Technology drowned.
Mr Ezra Njenga, a fourth-year actuarial science student, reportedly drowned while swimming near the falls with friends.
It remains unclear what transpired but witnesses said he was overwhelmed by the rapids.
It has now been seven days since the search for his body began at River Sagana. Heavy rains have hampered the operation.
Mr Njenga's friends tried in vain to rescue him.
Divers and the Nyeri County Disaster Management team were dispatched the next morning to help find the body.
More divers were sent to the river on Monday morning but they could not search as the water level had risen to the extent of submerging the bridge.
Central Regional Commissioner Wilfred Nyagwanga on Sunday visited the scene and ordered that the area be cordoned off and the road closed until the level of water subsides.
The commissioner ordered the arrest of thrill-seekers who swim in the area and other danger zones mapped out across the region.
Mr Nyagwanga said anybody caught swimming in the areas will be deemed to be attempting suicide, which is illegal.
“They can come for excursions but watch from a safe distance as this is a dangerous zone. If you are caught trying to get into the water, one can only assume you are attempting suicide so the law will take its course,” he said.
The waterfall has, over the years, attracted hundreds of domestic tourists but continues to claim lives.
In 2018, two people drowned while swimming there.