Residents of Mombasa are currently buying water at Sh100 for a 20-litre container despite the onset of rains.
The most affected areas include Changamwe, Mikindani and Likoni where residents are facing an acute water shortage.
Mombasa is among towns in Kenya where clean water for domestic use is still scarce even during rainy seasons.
According to the Chief Executive Officer, Heritage Hotels Kenya, Mohammed Hersi water vendors have taken advantage of the scarcity of fresh and clean water to exploit residents.
"There is still a big problem in Mombasa, that we are buying water at Sh100 for every 20-litre container despite the existence of the Indian Ocean that would be supplying million of clean water," he said on Sunday.
He said the county government under the leadership of Governor Hassan Joho should speed up efforts to construct a water purification plant to put to end the water scarcity problem in Kenya's second largest city.
Most of the water currently consumed domestically in Mombasa comes from Kwale and Taita Taveta counties.
The Mombasa county government in 2013 signed a deal with a Japanese company that was to establish a water purification plant but the factory is yet to be constructed.
Mombasa has no fresh water source.