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Water Pump Buying Guide

Choosing the right water pump for your application can be difficult as there are several different factors to consider. The good news is that our experts are here to help! In this guide, we explain the different types of water pumps, how they work, what you can use them for, and how you can determine which one is right for your requirements. We’ll also cover key features and accessories to help you choose the right pump (and corresponding parts). 

What is a Water Pump?

The term water pump is a broad name for a type of device that moves water or other liquids from one point to another. There are several different types of water pump available, with each suited for specific purposes and conditions. The most common uses for a water pump include:

  • Water Supply: Water pumps supply clean water from wells or treatment plants to homes.
  • Agricultural Irrigation: Water pumps draw water from rivers, lakes or wells to irrigate crops.
  • Septic Systems: Water pumps help move sewage from homes to septic tanks, or from the tank to a drain field.
  • Flood Control: Water pumps remove excess water during heavy rains or natural disasters, preventing damage and aiding recovery efforts.
  • Swimming Pools: Pool pumps circulate water through filters to keep the water clean and safe.
  • Ponds & Lakes: Pumps that ensure proper water circulation and oxygenation, creating a healthy environment for aquatic life.

Types of Water Pumps

Surface Pumps

Surface pumps are positioned above water level and are typically made to be installed separately from the water or liquid you wish to work with. Surface pumps tend to be for sources of superficial or surface water, as opposed to other kinds of pumps, which are designed to operate in deep water. For this reason, surface pumps are often used for crop irrigation, to circulate ponds and fountains, to transport water to sprinklers, or to move water for treatment before it is supplied to houses and commercial spaces.

Submersible Pumps

Submersible pumps are designed to operate underwater, or submerged in the liquid that the pump itself is pumping. A submersible pump operates by pushing, as opposed to drawing liquid, during the pumping process. The main applications of a submersible pump include ponds, grit and wastewater, sewage treatment, sump pumping, and dredging.

With this type of pump, only the discharge pipe and the power supply cable are visible above the surface.

Clean Water vs. Dirty Water

Submersible pumps come in different models, and they tend to distinguish themselves in terms of the water that needs to be pumped: clean, dirty or chemical water. 

As their name suggests, clean water pumps are suitable for water sources that don’t contain impurities, such as solid particles or debris. Dirty water pumps, on the other hand, can handle water with much bigger particles and debris in, without clogging or causing damage to your pump. You might see them referred to as trash pumps, which are also designed for moving large amounts of dirty water.

There are also chemical pumps, which are designed to withstand abrasive and corrosive liquids, chemicals, or sea water. The construction of chemical water pumps involves corrosion-resistant alloys to ensure it lasts when dealing with harsh substances. 

Borehole Pumps

Borehole pumps – multiple stage submersible pumps – are designed to draw water from deep underground sources. They are specifically built to function within boreholes, which are slim, deep wells drilled into the Earth’s crust. For this reason, they are often used in water extraction (abstraction), water wells, and oil wells.

Water Booster Pumps

Water-boosting pumps are used to increase water pressure in systems with low water pressure and flow rates. A booster pump is self-priming, which means that it draws water from the source and then applies high pressure to use it. 

Lifting Stations

A lifting station of one or more dirty water pumps and a storage tank. It works by collecting and then pumping waste to the sewer system at high pressure. In other words, a lifting station is used to move wastewater from lower to higher elevations until gravity takes over, which is useful if you are too far from the mains drainage system or below the level of the sewage network. 

Engine-Driven Pumps

Engine-driven pumps are powered by petrol or diesel engines, making them suitable for pumping/draining large quantities of water for long periods of time, or remote areas without access to power. They are commonly used in construction, agriculture, and emergency flood situations.

Electric Pumps

Electric-powered water pumps, on the other hand, are great for indoor use as they need to be plugged into a power outlet.

Key Features to Consider

As well as the liquid you wish to transfer and the type of pump you need, you also need to consider the following factors. 

Flow Rate

Flow rate, often measured in litres per minute (LPM), indicates how much water the pump can move in a specific time frame. Drip irrigation is most often noted per hour (LPH), while larger or high pressure systems are noted per minute (LPM).

Pressure Requirements

Pressure, measured in pounds per square inch (PSI), determines how fast water is pumped. High pressure is essential for water-boosting applications and long-distance water transfer. 

However, note that the smaller the cross-section of the pipe, the higher the pressure, regardless of flow rate.

Additional factors in your irrigation system can affect pump selection, including discharge head and suction lift.

Discharge Head

The discharge head is the maximum height reached by the discharge pipe after the pump.  

Suction Lift

Suction lift depth of water which can be pumped by a surface or a submersible pump. Most pumps are designed to push, not pull water, and are often not designed to lift water more than 25 feet.


As water moves through your system, friction loss can occur, which reduces pressure. Friction loss should also be considered. 

Total Dynamic Head (TDH)

Total Dynamic Head, or TDH for short, combines the discharge head and the suction lift, minus the friction loss. It determines the various losses that the pump must overcome, and represents the total height the pump can move water in feet. In other words, it is the work to be done by a pump, per unit weight, per unit volume of fluid.

Water Pump Accessories

When choosing a water pumps, make sure to consider the parts and additional accessories you’d like it to include, such as: 

  • Self-Priming: Pump and hoses do not need to be full of water before switching on.
  • Inlet Hose: Designed to bring water into the pump from the source. 
  • Discharge Hose: Directs the water away from the pump to the desired location. 
  • Inlet Strainer: Prevents debris and large particles from entering the pump, protecting the pump from damage and clogs.
  • Check Valves: Prevents backflow of water into the pump. 
  • Float Switch: Automatically turns the pump on and off based on the water level, preventing dry running and overflow.
  • Overload Protection: Protect the pump’s motor from overheating by automatically shutting it down if it gets too hot.
  • Rain Covers: Protect the pump from the elements.


Whether you’re a homeowner looking to keep your pond clean or a professional in need of an industrial water pump for a larger scale job, there is a water pump available to meet your needs. Choosing the right water pump does require you to consider what you need your water pump for, the ideal flow and pressure rate for your application, and if you need any specific features or accessories to get the job done. 

Looking for a premium water pump? At Generators Direct, we offer a range of petrol and diesel water pumps for your specific needs from a range of top-rated brands. All of our products are manufactured, tested and certified to industry standards, and come with a price promise – you won’t find prices cheaper anywhere on the web, but if you do, we’ll match them. In addition to this, all orders come with free mainland UK shipping and after sales support from our experts.

If you require additional advice or have a question for our team, don’t hesitate to get in contact with us using this form or via phone at +441639849847.