I replied to Scherry in a private message. The information may be useful to others. I explained that CV is a dessert and gets very little rainfall, except for the 4 mountainous islands where precipitation occurs on the leeward side of the mountains. Those islands are Santiago, Fogo/Brava, Santo Antão and São Nicolau. This is where there are any meaningful well water reserves, but they are deep down. The wells are thus dug close to the coast which results in risk of saltwater contamination.
In any event, any well water is used primarily for irrigation and private individuals must apply for a license to dig wells. Such licenses are granted only to farmers because well water is so scarce.
Finally, Cape Verde does not have a drinking water supply problem. Although there is very little rainfall, we are surrounded by the ocean on all sides. Thus, desalination plants exist on all islands and supply water to almost the entire population. However, not everyone has the economic means to pay for water. And a portion of the population lives in zones where the public water distribution network does not reach or would be too expensive to reach. So these residents have to carry water from distribution points to their homes, or they purchase water from water trucks which they use to fill up the barrels in which they store the water.
