Namibia is an arid country that is regularly afflicted by droughts. Large rivers flow only along its northern and southern borders, but they are far from the population centers. They are also far from the country's mines, which are large water users. In order to confront this challenge, the country has built dams to capture the flow from ephemeral rivers, constructed pipelines to transport water over large distances, pioneered potable water reuse in its capital Windhoek located in the central part of Namibia, and built Sub-Saharan Africa's first large seawater desalination plant to supply a uranium mine and the city of Swakopmund with water. A large scheme to bring water from the Okavango River in the North to Windhoek, the Eastern National Water Carrier, was only partially completed during the 1980s.
Most urban residents have access to drinking water supply, but access lags behind in rural areas. Access to sanitation also considerably lags behind access to drinking water supply. The bulk water supply infrastructure is owned by NamWater, a public entity operating under commercial principles. It sells water to the mining companies, as well as to the municipalities which in turn sell it to urban residents and businesses.
Water resources
Namibia's climate is hot and dry with erratic rainfall during two rainy seasons in summer. Within Africa its climate is second in aridity only to the Sahara. Namibia shares several large rivers, such as the Orange River in the South, shared with South Africa, as well as the Zambezi and Okavango Rivers in the North, shared with Angola, Zambia and Botswana. But these rivers are far away from the population centers and the cost of tapping them for drinking water supply is prohibitive. Only the Cunene River, which is shared with Angola, provides drinking water for four Northern regions of Namibia. The total average "safe yield" of Namibia's water resources is estimated at 660 million m3/year, distributed as follows: groundwater 300 million m3/year, ephemeral rivers 200 million m3/year, perennial rivers 150 million m3/year and unconventional sources such as treated wastewater 10 million m3/year.
Groundwater
Groundwater is distributed unevenly over the territory of Namibia, thus making the construction of pipelines necessary to tap their potential. In particular, the coastal area is nearly devoid of groundwater. Recharge in these areas is low and unreliable, groundwater lies at great depths and sometimes is of poor quality. Other areas are favorable, sitting on high-yielding, very productive aquifers that contain more water than farmers and communities presently need. Numerous small springs throughout the country sustain wildlife, man and livestock. Over the past century, more than 100 000 boreholes have been drilled in Namibia. Half of these are still in operation. In 2012 hydro-geologists discovered a huge aquifer in Northern Namibia that could supply the area, where 40% of the population of the country lives, for 400 years. The aquifer, called Ohangwena II, contains about 5 billion cubic meters of water which is up to 10,000 years old. The aquifer is about 300 meters deep and is under pressure, so that its water could be pumped up at a relatively low cost. However, a saline aquifer sits on top of the freshwater aquifer, so that drilling must be done carefully in order to avoid saline intrusion. The aquifer receives some recharge from Angola in the North. Experts recommend that, during normal climatic conditions, water abstraction should be limited to the inflow from the North in order to manage the aquifer on a sustainable basis. However, during extended droughts induced by climate change, the aquifer can be drawn down and serve as an important buffer against drought.
In some areas, groundwater is slightly saline (brackish). In the Omusati Region in Northern Namibia, four small brackish water desalination plants were installed in 2010 as part of the German-Namibian research project CuveWaters. The plants are powered by solar energy and provide between 0.5 and 3.3 m³ of safe drinking water per day, enough to satisfy the basic needs of between 10 and 66 people. At 15 Euro/m3 the cost of desalinating brackish water in these small plants is very high.