What type of pump is best for a borehole?

Choosing the right borehole pump feels overwhelming.
Making the wrong choice leads to wasted money, low water pressure, or even premature pump failure.
The "best" pump isn't a single model; it's the one that perfectly matches your borehole's specific needs.

The best pump for your borehole depends entirely on its depth and your required water volume.
For very deep boreholes with low volume needs, a screw pump is best.
For shallower boreholes where high water volume is the goal, a multi-stage centrifugal impeller pump is the ideal choice.

There is no single "best" pump for every borehole.
Thinking in those terms can lead to a costly mismatch.
Instead, the selection process is a journey of matching the right technology to your unique situation.
A borehole on a remote cattle station in Australia has very different requirements from one used for small-scale irrigation in Africa.
One requires extreme reliability and corrosion resistance, while the other needs to be economical and efficient.
The two key factors that will guide your decision are head and flow.
Head is the vertical distance you need to lift the water.
Flow is the volume of water you need in a certain amount of time.
Understanding how these two factors influence pump design is the first and most critical step.
Let's explore the pump types designed to master these different challenges.

For Deep Boreholes: The Screw Pump Solution

Your borehole is extremely deep.
You worry that no solar pump can reach the water efficiently.
A screw pump is specifically engineered for high-pressure lifts, conquering depths that other pumps cannot.

A solar screw pump is the best choice for very deep boreholes (typically over 80–100 meters).
Its unique positive displacement design creates immense pressure to lift water from great depths, making it perfect for domestic water supply and livestock watering.

When depth is your primary obstacle, you need a pump that specializes in building pressure.
This is the domain of the solar screw pump, also known as a progressing cavity pump.
It operates on a principle of positive displacement, which is fundamentally different from a standard centrifugal pump.
Instead of using speed to fling water, it uses a mechanical screwing action to methodically push sealed pockets of water up the pipe.
This method is incredibly effective at generating high pressure, which is what allows it to overcome the immense weight of a water column in a very deep well.
A screw pump dedicates the motor's energy to this lifting action.
This makes it the undisputed champion of high-head applications.
The trade-off for this incredible lifting power is a lower flow rate.
However, for many applications, this low-and-slow approach is not only acceptable but ideal.
It is perfect for reliably filling a storage tank throughout the day, providing drinking water for a household, or supplying a remote livestock trough.
This makes it an indispensable tool for off-grid living in areas with deep water tables.

How Screw Pumps Master Deep Boreholes

The power of a screw pump comes from two simple, robust components:

• The Rotor: A single, helical screw typically made from durable stainless steel.
• The Stator: A rubber sleeve with a matching internal double-helix shape.

As the motor turns the rotor, it meshes with the stator to create a series of sealed cavities.
These cavities trap a fixed volume of water.
With each rotation, these pockets of water are forced to "progress" up the pump body.
Because the cavities are sealed, the water has nowhere to go but up.
It cannot slip backward, which is why the pump can maintain pressure and lift water from extreme depths so effectively.
This positive displacement action also gives the screw pump another key advantage for boreholes.

Why It's Great for Boreholes

1. Handles Great Depths: Its ability to build high pressure is unmatched, making it the go-to solution for wells deeper than 100 meters.
2. High Sand Resistance: The flexible rubber stator can tolerate small sand and silt particles passing through without significant damage. This is a huge benefit for newly drilled or naturally sandy boreholes.
3. Consistent Flow: The flow rate is less affected by changes in head, providing a more predictable water supply.

Understanding the Performance

The screw pump is a specialist.
It sacrifices high volume for high pressure.
This makes it perfect for applications where a steady, reliable supply from a deep source is more important than a large gush of water.

For High Volume Needs: The Impeller Pump Family

You need to move a lot of water for farm irrigation, not just fill a home tank.
A screw pump's slow flow rate simply won't do the job.
The impeller pump family is designed specifically for high-volume water transfer.

A multi-stage centrifugal impeller pump is the best choice for boreholes where high water volume is the main priority.
It excels at delivering a large flow rate for irrigation and farming from shallow to medium-depth boreholes (typically up to 80 meters).

When your primary goal is to move a large quantity of water, you need a different kind of tool.
This is where the centrifugal impeller pump family excels.
These pumps work on a completely different principle than screw pumps.
They use a spinning impeller to grab water at its center and fling it outward at high speed using centrifugal force.
This action creates both flow and pressure.
To make them suitable for boreholes, these pumps are "multi-stage."
This means multiple impellers are stacked on top of each other in a series.
Water is energized by the first impeller and then directed into the center of the next one, which adds more energy, and so on.
Each stage adds more pressure, increasing the total head the pump can lift.
Even with multiple stages, the core strength of these pumps is moving a high volume of water efficiently at moderate depths.
For a farmer, this high flow rate is essential.
It means running multiple sprinklers, irrigating a larger area in less time, or quickly filling a large reservoir.
This makes centrifugal impeller pumps the workhorse of solar-powered agriculture across the globe.

A Critical Choice: Plastic vs. Stainless Steel Impellers

Once you decide on a centrifugal pump, you face another important choice: the material of the impellers.
This decision impacts cost, durability, and the pump's suitability for your specific water quality.

Plastic Impeller Pumps

These are the economical and versatile choice for many applications.
The impellers are made from high-strength, wear-resistant engineering polymers.

• Advantages: They are lightweight, which makes them easier to install. Their cost-effectiveness makes solar pumping accessible to a wider market. They also have excellent resistance to abrasion from fine sand.
• Best For: General farm irrigation, garden watering, and domestic water supply in areas with non-corrosive water and moderate depths.

Stainless Steel Impeller Pumps

These represent the premium, high-durability option.
The impellers and often the entire pump body are made from SS304 stainless steel.

• Advantages: They offer superior resistance to corrosion from acidic or alkaline water. They provide a longer service life and higher reliability in harsh conditions.
• Best For: Boreholes in regions with known water quality issues, such as the alkaline soils of Australia. Also ideal for high-end residential or commercial applications where longevity is the absolute top priority.

Matching the Impeller to Your Borehole

Use this table to guide your decision:

The Unseen Hero: The High-Efficiency Motor

You focus only on the pump itself—the part that touches the water.
You might overlook the motor that drives it.
An inefficient motor wastes precious solar power, forcing you to buy more panels and raising your total system cost.

The best borehole pumps are all powered by a high-efficiency Brushless DC (BLDC) permanent magnet motor.
This core component is the "engine" that determines the entire system's efficiency, reliability, and long-term operating cost.

Whether you choose a screw pump for depth or an impeller pump for volume, the motor that turns it is just as important.
The pump end and the motor form a partnership.
A great pump with a poor motor will deliver poor performance.
The gold standard in modern solar pumping is the Brushless DC (BLDC) permanent magnet motor.
Traditional DC motors use carbon brushes to transmit power to the rotor.
These brushes wear down over time, create friction, generate heat, and eventually need to be replaced.
BLDC motors eliminate these brushes entirely.
Instead, they use an intelligent electronic controller to switch the motor's electromagnetic fields.
This design is a massive leap forward in efficiency, reliability, and lifespan.
With efficiencies regularly exceeding 90%, these motors convert more of the sun's energy directly into the work of pumping water.
This has a powerful ripple effect on the entire system.
A more efficient motor requires less power to do the same job.
This means you can achieve your desired water output with a smaller, less expensive solar panel array.
Over the life of the system, this adds up to significant cost savings and a much faster return on your investment.

What Makes BLDC Motors the Best Choice?

The advantages of a BLDC permanent magnet motor are clear and substantial.

• Unmatched Efficiency: With efficiency over 90%, they waste very little energy as heat. This means more water pumped per watt of solar power.
• Exceptional Durability: The lack of brushes to wear out means there are no common failure points. They are designed for a long, maintenance-free life, which is critical for a pump installed deep inside a borehole.
• Powerful Performance: These motors produce high torque even at low speeds. This is especially useful for starting up under load, like when a pump is full of water.
• Compact and Lightweight: Advanced designs using powerful neodymium magnets make these motors significantly smaller and lighter than older motor technologies. This simplifies transportation and installation.

The System-Wide Impact of an Efficient Motor

Choosing a pump with a high-efficiency BLDC motor is a strategic decision that benefits distributors and end-users alike.

The motor is truly the heart of the solar pumping system.
Insisting on a high-efficiency BLDC motor ensures you are getting the best possible foundation for a reliable and cost-effective water solution.

Conclusion

The best borehole pump is the one that fits your specific needs.
Choose a screw pump for deep wells and an impeller pump for high volume, ensuring it's powered by an efficient BLDC motor.

FAQs

What size pump do I need for a borehole?

Size is based on head (depth) and flow rate (LPM), not just horsepower.
Calculate your total dynamic head and required daily water volume first to determine the right size.

How deep can a borehole pump go?

A standard centrifugal pump may reach 80-100 meters.
A specialist screw (helical rotor) pump can efficiently lift water from boreholes over 150-200 meters deep.

Which is better, a submersible or surface pump?

For a borehole, a submersible pump is required.
Surface pumps cannot lift water from depths greater than about 7 meters and are used for ponds or shallow wells.

How do I choose a borehole pump?

First, know your borehole's depth and your daily water needs.
Second, choose between a screw pump (deep/low flow) or an impeller pump (shallower/high flow).
Always select a high-efficiency model.

Can I run a borehole pump on a generator?

Yes, especially with an AC/DC hybrid pump controller.
This system automatically switches to generator or grid power when solar energy is unavailable, ensuring a 24/7 water supply.

How long does a borehole pump last?

A quality submersible pump with a brushless motor can last for 10+ years.
The key to longevity is matching the pump to the application and ensuring proper installation.

What is the maintenance on a borehole pump?

Modern solar submersible pumps with BLDC motors are virtually maintenance-free.
There are no brushes to replace, and the sealed bearings are lubricated for life.