How to Select Irrigation Pump

Richard Sun

Richard Sun

20 years experience in pump manufacturing

What is an Irrigation Pump?

An irrigation pump is a type of pump that transports water meant for irrigating crops. The prime mover of this pump is either an electric motor or a diesel engine. The prime mover provides the energy used to transport water from its source to the required destination. This pump operates by using motion, either rotary or reciprocating. This motion creates a state of low pressure commonly known as a vacuum. With a vacuum, fluid is forced to move from its storage/source into the pump. Due to the motion of internal parts, water gains kinetic and pressure energy allowing it to move to the required destination.

How does irrigation pump work?

Irrigation pumps are centrifugal pumps. As the name suggests, these pumps operate by use of centrifugal force. The pump’s main parts include a prime mover, shaft, coupling, impeller, and casing. The prime mover provides rotational power to the shaft. The impeller is usually mounted on the shaft. As such, shaft rotation causes the impeller to rotate. Due to impeller rotation, a vacuum is created inside the pump causing the water to be sucked from its source into the pump. When the water gets inside the pump, and due to impeller rotation, it gains more kinetic energy, and it proceeds to the casing. Inside the casing, the water velocity (kinetic energy) reduces while pressure energy increases. The pressure energy ensures the water has the energy required to flow to the required destination. This pump type is suitable for all type of irrigation such as sprinkler, lateral, centre pivot and furrow irrigation. The figure below shows the components of a centrifugal irrigation pump and its working mechanism.

Figure: Working of the centrifugal pump (

Types of Irrigation Pumps

There are various centrifugal irrigation pump types designed for use in crop irrigation. They are as discussed below:

Mono-block irrigation pump

This machine does not have a coupling common in other pumps. A single shaft connects the electric motor and the impeller. The use of this design helps to reduce the pump cost. It also ensures less power wastage associated with the use of a coupling in other pumps. Main characteristic of this device is that the suction and discharge ports are oriented at a right angle to each other. It is a very common pump in the market.

Figure: Mono-block irrigation pump


  • Simple design that makes repair, cleaning, and maintenance easy.
  • Small in size relative to other pumps.
  • Less power wastage since it does not have coupling relative to other pumps.
  • It is cheaper than other centrifugal irrigation pumps.
  • Versatile in size to suit different flow rates and heads.
  • Easy to install.
  • High flow rate.
  • High efficiency.
  • High reliability due to superb design.
  • Cost-effective


  • It needs priming before use.
  • Flexibility is limited since the pump and motor are connected via one shaft.
  • It may suffer from overheating, especially if used beyond its capacity.
  • It is prone to cavitation.
  • It uses only one impeller.

Self-priming irrigation pump

This pump is special in that it primes itself before the normal pumping process starts. As such, the operator does not need to manually add water inside the pump to perform normal priming, which is common on other pumps. When the pump is turned on, its impeller rotates, creating a vacuum. As such, water is drawn from its source into the pump. The water mixes with the air inside the pump. Since air has low density, it rises above the water. The air-water mixture rises up the pump towards the exit port, where air on top is discharged, and water goes back to the pump reservoir. The water then mixes with the remaining air and moves up again. The process repeats until all the air is removed, and then normal water pumping starts.

Figure: Self-priming pump removing air



  • Ability to prime itself.
  • Versatile in size to suit various heads and flow rates.
  • High flow rates.
  • Low maintenance costs.
  • Easy installation and repair.
  • Priming takes less than one minute.
  • Easy to operate.
  • It is able to handle water with suspended solids.
  • Highly reliable and durable.
  • Compact and simple design.
  • Resistant to corrosion.


  • It needs priming when it is new or after staying for a long time without use.
  • Efficiency is relatively lower than other pumps.
  • Relatively high initial cost.

Submersible irrigation pump

This pump, as the name suggests, operates while submerged in the water being pumped. It is suitable for pumping water from boreholes, deep underground tanks, and similar cases. The manufacturer designs the pump with a hermetically sealed body to ensure no single drop of water enters the pump. Water getting inside the pump would damage the pump motor and other electrical components, rendering the pump inoperable. The pump is designed with a power cable that transmits power from the mains supply socket to the pump. Also, the pump has a control system that allows the user to turn it on/off without needing to remove it from deep underground.


  • It operates while submerged in the water.
  • It does not allow water permeation.
  • It is operated while submerged in the water.
  • It has a long service life.
  • Highly reliable and cost-effective.
  • It is self-priming.
  • High efficiency.
  • High flow rate and pumping head.
  • Versatile in size.
  • Resistance to corrosion.
  • Compact and simple design.


  • High initial cost relative to other pumps of the same capacity.
  • Inspection, repair, and maintenance are a challenge.
  • It is prone to cavitation.

Split case irrigation pump

Split case irrigation pump

This pump is made up of two casing chambers. The two chambers are connected together using bolts and nuts. Some designs have two suction ports, allowing double suction and, thus, a high flow rate. These pumps are made of strong metallic materials that guarantee safety against high pressure and corrosion. There are two types: the vertical type and the type. Vertical split types have less footprint relative to the horizontal type of the same capacity. This device is suitable where high pressure is needed. The horizontal type is the most common of the two types. It is suitable for use where water is needed at constant pressure and long working hours.

Figure: Split case irrigation pump



  • Highly reliable compared to most other pumps.
  • High flow rates of 3500 m3/hr
  • Ability to work for many hours without overheating.
  • Double suction capabilities.
  • Easy to assemble and disassemble.
  • Resistant to corrosion.
  • Ability to withstand high pressure.
  • High durability and reliability.
  • Available as single or double suction.
  • Easy access to internal components.
  • Easy installation, repair, and maintenance
  • Available in a variety of sizes.
  • Resistant to corrosion.
  • High efficiency.


  • Highly expensive relative to other pumps.
  • Low flexibility relative.
  • Large in size and thus heavy in weight.
  • Needs priming.
  • Prone to cavitation.

Solar-powered irrigation pump

This is a special type of pump that is powered by solar energy. The pump uses photovoltaic (PV) solar panels that harvest solar energy and transmit it to the pump. The pump consists of solar panels, a charge controller, circuit breakers/fuses, and electrical cables. The pump operates similarly to other centrifugal pumps where it rotates the impeller when turned on, and thus, it proceeds to generate pressure and kinetic energy responsible for transporting the water to the required location. This pump is applicable in almost all types of irrigation such as furrow irrigation, terraced irrigation, sprinkler, centre pivot and lateral irrigation.

Figure: Solar powered pump for irrigation (


  • Easy to repair and maintain.
  • Environmentally friendly.
  • Suitable for remote areas.
  • Easy installation.
  • Highly reliable.
  • Long service life.
  • Low maintenance requirements.
  • Portable.
  • No fuel costs.
  • Low labour is needed.


  • High up-front costs.
  • It cannot operate at night or during cloudy weather.

Diesel powered irrigation pump

This is a pump that is powered by a diesel engine. The pump and engine are assembled together as one unit. It is suitable for use where the water source is far from the mains electricity supply. Rotation of the engine crankshaft helps to rotate the pump shaft and thus impeller rotates allowing fluid flow. This pump can be used for sprinkler, lateral, and centre pivot irrigation.

Figure: Diesel powered irrigation pump ( ).


  • Highly portable.
  • Suitable for use in remote areas.
  • Versatile in size.
  • Long service life.
  • Wide range of flow rates and head.
  • Easy to install and repair.


  • Expensive to maintain and operate.
  • High energy consumption.
  • It needs priming.
  • Heavy relative to other pumps.

Steps for Choosing the Right Irrigation Pump

Determine the water requirements

There are various factors to consider in this first step. They include:

  • Volume of water. The question to answer here is, “How much water is required per day?”
  • Next determine the source of water. For example, if the water is from a deep well, then a submersible pump would be best. If the water is from a shallow well or from a river, a mono-block pump, split case pump, self-priming pump would fit well.
  • Pump capacity and size. Based on the water volume needed per day, estimate the pump size and capacity. If not sure on how to do the calculation, you can consult pump experts who, based on the daily water requirements will give you variety of pumps that would serve you better. Select one that would serve you best.
  • Maintenance and durability. The pump expert will give pump options, but ensure you select the one that is made of strong materials. This will ensure resistance to corrosion. Also, select the one that would not fail too often since it would end up draining your pockets with frequent repairs and maintenance.
  • Budget. In this case, try to compare the various pump options and their prices. Also, consider installation charges, energy consumption, and maintenance costs. In conclusion, select a pump that fits your budget, but ensure that it fulfils your pumping requirements.

Size the pump properly.

To establish the best irrigation pump, factors like pressure and flow rate should be considered. This will ensure that the pump matches your water supply needs. As such, calculate optimal pump size based on head range, flow rates, and operating conditions. If you select the pump properly, you will get the one that will efficiently meet your daily water requirements without underperforming or overloading. In addition, a properly sized pump will be cheap to run since it will not break down frequently. Also, it will not consume excessive power. There are four key factors that will help you select an ideal irrigation pump that is:

  • Pressure and flow rate. Flow rate refers to the volume of water needed in a certain period of time. It is measured in terms of m3/hour, litres per minute (LPM), or gallons per minute (gpm). So, how much water do you need in one hour? Ensure the flow rate and pressure demands match the pump that will be purchased.
  • Outlet/inlet size. Ensure the pump matches the size of the plumping system, that is, ensure the inlet and outlet ports match the pipe sizes for efficient water transfer. Also, this will ensure the pipes and valves do not leak due to excess pressure.
  • Vertical height (Head range). What is the vertical distance the pump will lift the water? This is a very crucial factor that will ensure the irrigation pump can effectively lift water from its source.
  • Horizontal pumping distance. This factor, together with the vertical height significantly affect ability of your pump to transfer water to the specific destination.

Pump specifications

  • Discharge rate. It is also known as flow rate. The higher the discharge rate, the quicker the pumping, and vice versa. Ensure the discharge rate matches the flow rate you need. This is also related to the amount of water you need per day.
  • Power demands. This is the amount of power the pump will need to serve you when it is in use. It is measured in horsepower (hp) or kilowatt (kW). The power demands depend on the total head and discharge rate. The higher the head and flow rate, the more the power is used, and thus, the more the energy cost.
  • Noise level. Select a pump that is designed with noise reducing features. This is necessary especially where the pump will be installed nearer to residential building. This will ensure no disturbance to those living around.
  • Construction materials. Check on what materials have been used to make your pump. In this case, it is advisable to select a pump made of corrosion resistant materials. This could be steel or high-quality thermoplastics. By selecting a pump with such materials, it will make it last for decades.

Check pump warranty

Check on pump warranty before you purchase. The warranty shows that the company is confident that they have sold you a perfect product. Again, if the pump had some flaws during manufacturing, it would mean that the manufacturer will be willing to exchange the faulty pump with new and good one.

Factors to consider when selecting an irrigation system

Type of soil

The soil type considerably affects the irrigation method employed as well as irrigation run times. Tight clay soils are able to hold moisture for long duration compared to sandy soils and thus they need lower rate of water application. On the other hand, sandy soils need frequent water supply to ensure moisture in the roots.

Topography of land

Centre pivot and travellers system should not be used on severely sloping or hilly land. A drip system would work better if the laterals were running along topographic lines.

Local weather patterns

Drip irrigation would work well in cases where there are high winds and also in arid zones with low humidity. However, in such cases, sprinklers would not work well since water losses would be extremely high.

Crop types

Drip and sprinklers need a high amount of investment. As such, it is recommended to use them in high-value crops such as orchard crops, small fruits, and vegetables instead of using them in crops like soybeans and wheat.

Quality of water

Drip irrigation systems need some sort of filtration. Also, overhead systems like sprinklers sometimes needs filtration. Test the water to check on water borne pathogens. Depending on irrigation method and crops used, chlorine injection could be necessary. Another water issue would be dissolved minerals and soluble iron.