As Tanzania faces rising demand for water driven by population growth, agriculture, industrialisation and climate change, the country is increasingly looking beneath the surface for part of the solution.
Groundwater, stored in underground rock formations known as aquifers, is emerging as an important component of Tanzania’s efforts to improve water security, particularly in areas where communities depend heavily on seasonal rivers, lakes and other surface sources.
According to the Tanzania Water Resources Atlas 2019, the country has an estimated 126 billion cubic metres of water resources suitable for various uses each year.
Surface water accounts for about 105 billion cubic metres, while groundwater contributes approximately 21 billion cubic metres.
The figures point to the significant role groundwater can play in supporting households, agriculture, livestock, industries and other economic activities.
But experts warn that increasing reliance on underground water must be accompanied by stronger monitoring and regulation to prevent over-extraction and contamination.
One of the most common misconceptions is that groundwater is always clean because it has passed through layers of soil and rock.
In reality, groundwater can become contaminated by activities taking place on the surface.
Poorly constructed toilets and septic tanks, uncontrolled waste disposal, agricultural chemicals, oil products, industrial activities and untreated wastewater can allow pollutants to seep into the ground and reach aquifers.
As a result, water that looks clean may not necessarily be safe for drinking.
This makes regular testing of groundwater quality essential, particularly before a newly drilled borehole is brought into use.
Testing also helps determine the quantity of water available and whether extraction levels can be maintained without damaging the underground resource.
The development of groundwater resources requires more than simply identifying a location and drilling.
Hydrogeologists and other water experts use modern technologies to investigate underground geological formations and identify areas with a higher potential for groundwater before drilling starts.
The process can provide information about the structure of rocks, underground water-bearing formations and the most suitable location for a borehole.
This approach can reduce the risk of unsuccessful drilling while providing information needed to manage the resource sustainably.
The Ministry of Water, through its Water Resources Department, coordinates the management of both surface and groundwater resources.
The Government has invested in equipment aimed at increasing its capacity to develop water infrastructure and respond to communities’ needs.
Among the measures is the acquisition of 25 sets of borehole-drilling equipment and five sets of equipment for dam construction.
The investment is expected to strengthen the capacity of government experts to support water projects while ensuring that groundwater development follows technical procedures.
Regulation of companies and individuals involved in groundwater exploration and drilling is also being strengthened.
Recent data shows that 45 drilling company licences, 45 drillers’ licences and 15 groundwater exploration licences have been renewed.
The figures bring the total number of valid licences to 93 for drilling companies, 106 for drillers and 20 for institutions and companies involved in groundwater exploration.
Meanwhile, 630 additional borehole drilling permits have been issued, bringing the total number of permits issued to 4,519.
The growing number of permits demonstrates increasing activity in groundwater development and underscores the need for effective oversight.Groundwater management also has a regional dimension.
Some underground water-bearing rock formations extend across national boundaries, meaning that excessive extraction or pollution in one country could affect water availability in another.
This makes cooperation with neighbouring countries important in managing shared groundwater resources.
Tanzania is involved in regional water management initiatives involving countries such as Burundi, Rwanda and Uganda.
The principle is simple: where an aquifer is shared, countries need reliable scientific information and cooperation to ensure that one country’s use does not undermine another country’s water security.
Kagera Region offers an example of efforts to improve understanding and management of groundwater.
A groundwater management project covering Muleba, Bukoba, Missenyi, Karagwe and Kyerwa districts was implemented at a cost of about US$5.33 million.
The project strengthened the capacity to collect information on groundwater quantity and quality and provided modern equipment for monitoring the resource.
Such information is important for planning because authorities need to know how much groundwater is available, where it is located, how it moves underground and how much can safely be extracted.
The case for better groundwater management is becoming stronger as climate change disrupts traditional water sources.
Changes in rainfall patterns, rising temperatures and prolonged dry periods can affect rivers, lakes and dams.
During droughts, groundwater can provide a more dependable source of water because it is less immediately affected by short-term changes in rainfall.
However, experts caution against viewing groundwater as an unlimited reserve.
If extraction exceeds the rate at which aquifers are naturally replenished, groundwater levels can decline, threatening the long-term availability of the resource.
For ordinary Tanzanians, protecting groundwater may appear to be the responsibility of water authorities and drilling companies. But much of the protection begins within communities.
Safe sanitation, proper waste disposal and responsible use of fertilisers and pesticides can help prevent pollutants from reaching underground water sources.
Industrial operators also have a responsibility to ensure that wastewater and other potentially harmful substances are properly managed.
For drilling companies and individuals, obtaining the required licences and permits is equally important.
Water Minister Jumaa Aweso has stressed that groundwater exploration and drilling should be conducted professionally and in accordance with the law, rather than being driven solely by commercial interests.
As Tanzania moves towards its long-term development ambitions, groundwater is likely to become increasingly important.
The resource can help expand access to clean water, support irrigation and livestock production and provide communities with an alternative source during periods when surface-water supplies decline.
But its value will depend on how responsibly it is managed.
The key challenge for Tanzania is therefore not simply to drill more boreholes. It is to ensure that every borehole is developed on the basis of reliable scientific information, appropriate permits and regular monitoring.
Groundwater may be hidden from view, but its importance to Tanzania’s future water security is increasingly difficult to ignore.
The resource beneath the ground can help secure the country’s water future but only if it is used wisely today.