But speaking at the site in Makueni, Uhuru assured that his administration will do all it can, including expanding the sewerage system in the capital, to ensure those downstream get clean water.
The President said that Thwake will offer relief to the residents of Makueni and Machakos who have suffered for years due to lack of water.
He said water from the dam will be piped to rural homes, Konza City and other areas within the region
Uhuru told off those who have been criticizing his administration's heavy investment in infrastructure.
He said infrastructure unlocks job opportunities for the population, besides other immense economic benefits.
Among those accompanying the President are ODM leader Raila Odinga, his Wiper counterpart Kalonzo Musyoka, governors Alfred Mutua (Machakos), Kivutha Kibwana (Makueni) and Kitui's Charity Ngilu.
A number of Cabinet Secretaries and top government officials hailing from the region were also present.
Only Uhuru, Kalonzo and Kibwana spoke at the event.
Kalonzo had invited Raila to speak but the former PM decided to give that opportunity to the host governor.
Kalonzo said the project will tremendously benefit the residents.
He, however, said the pollution of the rivers upstream is a major concern and urged the President to address it.
"The big concern is about pollution of Athi River. This is the biggest challenge. But we want to assure the country that this is a serious project that will transform the lives of the people and improve the environment," he said.
