By Raeli Hydro
Manual borehole drilling is a traditional method of accessing underground water using human-powered tools and relatively simple drilling equipment. Unlike modern mechanical drilling, which uses large rigs, compressors and engines, manual methods depend mainly on physical labour, hand-operated tools and basic mechanical systems.
Manual drilling can be useful in areas where groundwater is relatively shallow and the ground formations are suitable. It can also offer a lower-cost option for small communities, households and projects with limited access to heavy drilling equipment. However, it is not suitable for every site. Ground conditions, groundwater depth and the required water yield must be considered before choosing the method.
What Is Manual Borehole Drilling?
Manual borehole drilling involves creating a narrow hole in the ground to reach an underground water-bearing formation. Workers use tools to loosen soil and remove the material from the hole.
Depending on the ground conditions, different manual techniques can be used. These may include hand augering, percussion methods and other simple drilling approaches.
The basic principle is straightforward. The drilling team gradually penetrates the ground, removes soil and rock fragments, supports the sides of the hole where necessary and continues until a suitable groundwater zone is reached.
A manual borehole is generally more practical in soft soils, sandy formations, clay and unconsolidated sediments. Hard rock can make manual drilling extremely difficult or impossible.
How Manual Borehole Drilling Works
The process normally begins with site selection. The drilling team needs to identify a location where groundwater is likely to be available.
Groundwater does not occur at the same depth everywhere. Some locations may have shallow groundwater, while others may require much deeper drilling. Local geological information, existing wells and professional groundwater assessments can help determine whether manual drilling is appropriate.
Once a suitable location is identified, the drilling area is prepared.
1. Preparing the Drilling Site
The team clears the selected area and establishes a safe working space. The drilling point is marked and basic equipment is assembled.
Depending on the chosen technique, equipment may include:
- Hand augers
- Drilling rods
- Cutting bits
- Rope and lifting equipment
- Buckets or bailers
- Tripods
- Casing pipes
- Water storage containers
- Basic pumping equipment
The equipment required depends on the soil conditions and the intended depth.
2. Starting the Borehole
The drilling process begins by placing the drilling tool at the selected point.
With hand auger drilling, the auger is rotated manually. Its cutting blades penetrate the soil and collect material. The auger is periodically removed from the hole so that the soil can be emptied.
The tool is then returned to the hole and the process continues.
This cycle is repeated many times.
As the borehole becomes deeper, additional drilling rods can be connected to the auger. This allows the drilling team to reach greater depths without requiring a large mechanical rig.
3. Removing Soil and Cuttings
Removing excavated material is one of the most important parts of manual drilling.
If soil is allowed to remain inside the borehole, it can obstruct the drilling tool and make further penetration difficult.
The drilling team therefore regularly removes the cuttings. Depending on the method, this can be done using an auger, bailer, bucket or similar tool.
The material removed from the hole can also provide useful information about the underground formation. Changes in soil colour, texture, gravel content and moisture can help indicate changes in geology.
4. Supporting the Borehole Walls
A major challenge in manual drilling is borehole collapse.
Loose sand, gravel and unstable soil can fall into the hole. This can make drilling difficult and may contaminate the groundwater.
To reduce this risk, workers may install temporary or permanent casing as drilling progresses.
Casing provides structural support to the borehole walls. It also helps separate the water-bearing section from unstable formations.
The type and diameter of casing depend on the design of the borehole and the geological conditions.
5. Reaching the Water-Bearing Formation
The main objective is to reach a suitable aquifer.
An aquifer is a geological formation that stores and transmits groundwater. When the drilling process reaches a water-bearing zone, the material removed from the hole may become noticeably wetter.
However, simply finding wet soil does not automatically mean that the borehole will provide enough water for a household or other use.
The yield, water quality and long-term sustainability of the source must be considered.
This is one reason why professional assessment is important before deciding to rely on manual drilling.
6. Installing the Screen and Casing
After reaching the target water-bearing formation, the borehole can be completed with appropriate casing and screen.
The screen allows groundwater to enter the borehole while helping prevent larger particles of sand and gravel from entering the water system.
A gravel pack may also be installed around the screened section where appropriate. This can help improve filtration and support the borehole structure.
Proper completion is essential because a poorly constructed borehole can produce muddy water, suffer from excessive sand production or become unstable.
7. Developing the Borehole
After construction, the borehole may need to be developed.
Borehole development involves removing fine particles and drilling residues from around the screened section. The objective is to improve the movement of groundwater into the borehole.
Depending on the construction method, development can involve surging, bailing, pumping or other suitable techniques.
The water may initially appear cloudy. Continued development can help improve clarity and reduce the amount of loose material entering the borehole.
8. Testing the Water
Finding groundwater is only part of the job.
The water should be tested before it is used for drinking or domestic purposes. Testing can identify physical, chemical and microbiological characteristics.
Water quality can vary considerably from one location to another. Groundwater can contain minerals or contaminants that are not visible to the eye.
Professional water testing therefore helps determine whether treatment is necessary.
Manual Borehole Drilling vs Mechanical Drilling
The main difference between manual and mechanical drilling is the equipment and drilling capacity.
Manual drilling normally uses simple tools and human labour. It can be cheaper and easier to mobilise in suitable locations.
Mechanical borehole drilling uses specialised drilling rigs and equipment. It can penetrate much deeper formations and is generally more suitable for hard rock and projects requiring higher production capacity.
Mechanical methods such as percussion drilling and Down-the-Hole drilling are commonly used where geological conditions are too difficult for manual techniques. Raeli Hydro provides specialised drilling methods for different geological formations and groundwater requirements.
The choice should therefore not be based on price alone. The geology, expected depth, required yield and intended water use are all important.
Advantages of Manual Borehole Drilling
There are several potential benefits to manual borehole drilling.
First, the equipment is usually simpler than a large mechanical drilling rig. This can make the method easier to transport to locations with difficult road access.
Second, manual drilling can require less initial equipment investment.
Third, the method can be suitable for shallow groundwater projects in favourable geological conditions.
It may also be useful for community water projects where the expected water demand is modest.
Limitations of Manual Drilling
Manual drilling also has significant limitations.
The biggest limitation is depth. Manual equipment cannot normally compete with modern drilling rigs when groundwater is located deep underground.
Hard rock is another major challenge. Volcanic rock, crystalline rock and other hard formations can require powerful mechanical drilling equipment.
Manual drilling can also take longer and require considerable physical labour.
Most importantly, not every location with groundwater is suitable for manual drilling. A method that works well in loose sediments may fail completely in hard or unstable formations.
Is Manual Borehole Drilling Legal in Kenya?
Anyone considering groundwater development in Kenya should follow the applicable requirements of the Water Resources Authority (WRA).
Kenya’s Water (Resources) Regulations, 2025 provide rules for groundwater development. The regulations state that a person intending to abstract groundwater must apply for authorisation from the Authority. They also provide specific requirements for boreholes and wells equipped with motorised pumps, including hydrogeological information, testing, professional supervision and completion records.
This means property owners should not simply begin drilling without checking the applicable requirements.
The correct approvals and technical procedures help protect groundwater resources and reduce the risk of poorly constructed water sources.
Why Professional Assessment Matters
Although manual drilling may appear simple, borehole construction requires technical knowledge.
Choosing the wrong location can result in a dry or low-yielding borehole. Poor casing can cause collapse. Incorrect screening can allow excessive sand into the water. Poor sanitation around the borehole can also create contamination risks.
For these reasons, groundwater development should be approached as an engineering and water-resource project rather than simply digging a deep hole.
Manual Borehole Drilling by Raeli Hydro
Raeli Hydro provides borehole drilling and groundwater solutions for different applications in Kenya. The company works with different drilling technologies depending on the geological conditions, required depth and water requirements.
Where manual drilling is suitable, the method can provide a practical way of accessing shallow groundwater. Where deeper or harder formations are encountered, a mechanical drilling technique may be more appropriate.
The best drilling method should always be selected after considering the site geology, groundwater potential, expected yield and intended use of the water.
For households, farms, institutions and businesses seeking a reliable groundwater source, professional planning can help reduce unnecessary drilling costs and improve the chances of developing a productive borehole.
Manual borehole drilling remains a useful groundwater development technique where the geological conditions are favourable. It combines simple equipment, human labour and careful borehole construction to reach shallow underground water.
However, it is not a universal solution. Groundwater depth, geology, borehole design, water quality and legal requirements all need to be considered.
With proper site assessment and construction, manual drilling can provide an affordable water source for suitable communities and properties. Where the ground is too deep or hard, modern mechanical drilling methods provide a more appropriate alternative.