The borehole will provide clean water for over 2,000 families living in the area.
Coast Regional Commissioner Rhoda Onyancha said the dam is only 10 per cent complete and is scheduled to be completed by 2027.
The water they use is untreated and collected from an area that has repeatedly triggered cholera outbreaks.
They have been forced to walk long distances to find the commodity and to share it with animals, risking water-borne diseases because of contamination, and attacks by wild animals.