Buyer's Guide to Water Pumps

Need to buy a water pump? Check out our buyer's guide to Water Pumps first.

Water pumps, transfer pumps, trash pumps, fire-fighting pumps...the world of water pumps isn't as easy it might first appear.

So why are there so many water pumps to choose from? The fact is there are many different situations in which you might need to pump water, and each one comes with various challenges. Whether you're draining a pond or your basement, or want to clear larger areas on a farm or worksite, protect your home from fire, each different type of water pump is designed to make your specific task easier.

water transfer pump
Water Pumps are used at home, on farms, construction sites, by councils and governments, emergency services and many more.

What is a water pump?

At its core, a water pump is designed to do one very simply thing: move large amounts of water from one place to another. As time's gone on, some good manufacturers have designed extremely efficient and durable pumps, so you can count on them when you need.

There are two main types of portable water pumps: electric powered and petrol/diesel powered.

Electric Water Pumps

The most common type of Electric Water Pumps are used for indoor smaller requirements; Rain water tank pumps, small garden pumps, aquariums, caravan pumps etc. Most can be plugged into your standard household mains power or 12 volt power source. They are typically designed for the DIY user for smaller domestic tasks, are often less powerful and require less maintenance than petrol/diesel pumps as there's no need to worry about changing oil and so on. Then are larger electric pumps (often three phase) for moving water over significant distances - these are often stationary water pumps.

These types of water pump have the obvious disadvantage that you are restricted to use where there's mains power and have to be connected (unless you use a generator). So they might not be the best fit for many portable uses including common farm/rural applications, unpowered worksites or on your property when there is a blackout.

Small Electric Water Pump for Garden

Petrol and Diesel Powered Water Pumps

The majority of portable pumps used on large properties, in farming, construction and mining and by professional contractors are powered by petrol or diesel, with a centrifugal design. A rotating impeller draws water from the pump and pressurises the flow of the discharge. Petrol or diesel powered pumps produce carbon monoxide emissions, so they absolutely must be used outdoors and are ideal for use on jobsites and for irrigation on a farm / large properties. They start just like your lawn mower; add fuel and oil, pull the recoil chord (or elec start for some models) and the engine is running ready to prime for pumping. There are many types of petrol/diesel water pumps that fall into this category, the main ones including:

Water transfer pumps: Dewatering pumps or "gushers" can transfer high volumes of water at relatively low pressure. Ideal for flood irrigation, fast fill tanker applications, and dewatering of construction sites. Essentially moving large volumes of water from one place to another.

Honda powered petrol water transfer pump: Great for high volume water transfer, fast fill tanker requirements, flooding irrigation and dewatering of construction/building sites

Fire fighting pumps: Pumps with higher pressure so it can pump water from your water source (creek, tank, dam, pool etc.) and discharge with pressure. Ideal for firefighting, fire preparation, high pressure water transfer, spray irrigation, high pressure spraying, wash down and more.

Are you fire ready? Crommelins Fire Fighting Pump in Action

Trash pumps: Pumps that can move water with debris and solids. Ideal for pumping muddy, mucky water on construction sites. For seriously thick sludge water, you may need a Diaphragm pump which works more like a vacuum.

Subaru Trash Pump can handle solids & debris up to 30mm in diameter for the medium sized de-watering tasks on the construction site, mining site, farm station or for rental applications.

The above are the most common types of pump, with other more specialised pumps including; chemical transfer pumps, sump pumps, diaphragm pumps and submersible pumps.

5 key things to consider in a portable water pump for sale:

1. Flow Rate: When it comes to buying a water pump, you need to know how quickly it's going to get the job done. The number you're looking for is litres of water per minute. Some portable water pumps can move as much as 2500 litres of water per minute (and above) - more than enough grunt for jobsites and farms before having to consider larger sized stationary pump. For home use, you might only need a 100 -200 litres per minute pump.

2. Inlet size: This consideration goes hand in hand with Flow Rate. Portable pumps generally have an inlet size ranging in size from 1" - 6" (sometimes more). Irrespective of the size, centrifugal pumps work the same way; sucking in water through an inlet valve and then ejecting it from a discharge valve. So the difference in size just means that larger pumps can get the job done faster; For example, if you need to empty a pond, any size pump will get the job done, but a 4" transfer pump will finish a job 4 times faster than a 1" transfer pump.

3. Maximum Head and Pressure: What is Maximum Head? It refers to the maximum height the pump can pump to (its a specification each pump manufacturer publishes for all their pump model and it is a combination of the suction height and pumping height). If you have a pump with a maximum head of 60 metres, your flow rate will be about zero at 60 metres of head. So, the flow rate diminishes with the height. Overall, you will want to choose a pump that has a max head higher than the height you need to pump. Charts are important to consider (see below) when choosing a pump, because again, delivery capacity falls away as max head capacity is approached.

As a handy rule of thumb, using the Maximum Head capacity of the pump will tell you what the pump can do in terms of; suction height + uplift. For example, if you needed to draw up water 2 metres from the water source to the pump, then move the water from the pump up a gradient of 25 metres, then you would need a pump with a maximum head greater than 27 metres (2 + 25). Also note that as water moves through the hosing and the bends it will encounter friction, causing some small additional head loss - another reason to choose a pump with maximum head larger than your height pumping requirements.

So then also worth considering is; at what pressure do you need the water to be discharged? If you need some pressure for fire fighting, water sprinkling etc., then you'll need to consider the pumps pressure rating (PSI). To work that out, you look at the pump's Max Head metre rating (detailed in the pump's specs); approximately 1 metre of max head is equal to 1.42 PSI. So you can simply multiply the maximum head of the pump by 1.42 to give you the max psi rating of that pump. For example, if a pump has a maximum head of 40 metres, then its max pressure is approx. 57 PSI. As a point of reference, a typical garden hose dispenses water at about 30-40PSI. Generally speaking, Transfer Pumps will have lower PSI capacity, but can move larger volumes of water (higher flow rates), whereas High Pressure Fire Fighting Pumps will have a higher PSI but move lower water flow rate volumes on a litres per minute measure.

Water Pump Curves

4. Type of water pumped: What type of water do you need to move? Transfer pumps or Fire Fighting Pumps are fine for clear water. If it contains debris or solids, you'll need a trash pump; these are quite common on construction sites. For sewage water or thick sludge you may need a diaphragm pump. If you want to pump agricultural or industrial chemicals, consider a chemical pump.

5. Pump Quality: Firstly consider the quality of the brand's pump and its componentry such as the engine/motor. Quite often, pumps are used for tasks in your business, for important things such as home protection from fire danger or for life on the farm; so you really want a pump that is dependable and can handle your watering demands. In which case, you'll want to look for a brand that offers a solid warranty and has a national service network that will look after you if any servicing or repair is required. Check out Water Master Pumps, which come with a two year warranty, are powered by Honda and Yamaha engines and have hundreds of accredited service agents around the country.

Check out our blog for more advice and information on water pumps and check out our specific pump buyer's guides for:

- Water Transfer Pump Buyer's Guide

- Fire Fighting Pump Buyer's Guide

- Trash Pump Buyer's Guide


DISCLAIMER* Please note, this advice is general in nature and we strongly recommend consulting the product manual and where relevant, a professional installer.

14 thoughts on Buyer's Guide to Water Pumps

6 September 2023
Thank you for sharing this informative article on Electric Water Pumps

5 September 2020
It is one of the best write up on the guide while buying the water pump.Before hitting on the other blogs I would request all to give a try here to get the best available content here. The article is much informative regarding work as well.

30 May 2020
what type of pump can I use to draw water from a dam and connect for drip irrigation for avocado farming?

My Generator Response
Hi Dylan, Thanks for your question. Unfortunately this is something we are unable to answer. We recommend going to an irrigation specialist. Thanks.

26 February 2020
Great info, we use alot of the same topics when referring customers to upgrade their existing pumps. I will definitely show them this!

16 October 2019
Thanks for your information on water pumps! I think we need a new one installed. I'll find a plumber to ask what is best for our home.

12 November 2018
Hi, just ran across this article. We want to use water from a dam to service garden via a 'normal' hose and are considering a 6.5hp pump with 2" connectors that includes 1" hose adapters - would that work for garden watering or is it too much (27m head but we've got a fair bit of ground to cover between dam and trees)?

7 February 2018
Hi not sure witch size pump I need, there is a 1.5in line running from my dam that hasn't been connected to a pump yet , do I need a 1.5in inlet or can I go 2in, thanks

My Generator Response
Hi Jay, it is always recommended that you use the same diameter hose/piping as the suction and discharge ports on the pump. While it is sometimes necessary to reduce that diameter, it is strongly advised that you do not reduce the hose size by more than half an inch. While you may see an increased pressure due to the slightly smaller piping, this will also see an increased backpressure on the pump. The more you reduce the hose/piping diameter, the more you increase this backpressure and likely cause the pump to fail and that would not be covered under warranty. Thanks

9 February 2017
I believe that pump reliability is paramount - it is important to satisfy the pump user through effective and efficient fluid management. This is a great blog post on what buyers should look for. We recently completed some work on MK Dons football stadium:

23 November 2016
I want to purchase water pump for irrigation. Land size is 40 Hectares.

My Generator Response
Hi Gurma, please contact us on 1300 400 122 to discuss your requirements in more detail. Thank you.

8 October 2016
Informative post! Though the first step towards detecting pump issues is to have right knowledge of what pump has been installed in the water system.The power of the pump is also a vital element. If the horsepower of your pump is more, the pump will function less, thus enhancing the life of the pump. Well, it's a knowledgeable post!

28 July 2016
Periodically I have to use a 3 inch line, Wacker Trash pump to dewater my personal property because of bad drainage. Moving the pump is difficult. Do they make pumps that can be permanently installed or either a 120 or 220 V that will move as much water as the trash pump? Thanks

My Generator Response
Hi, you could look at a permanently installed electric drive trash pump - these kind of pumps are designed for a wide range of industrial and agricultural applications. Unfortunately we don't stock those kind of electric drive pumps, we only stock the portable petrol and diesel style trash pumps. For maneuverability with a petrol or diesel trash pump, you could look at a wheel and handle kit as an optional accessory. Thanks

1 May 2016
A very interesting and useful article. It confirms the type of pump I need, a small electric one, but I am somewhat at a loss to work out exactly what I need. I want to pump water up to a height of 2 metres through a 15mm pipe and then through a coiled length of approx 100m and down 2m, the inlet flow rate is 4-5 litres per minute. I would appreciate any advice you could give me.

My Generator Response
Hi Jaak, if you haven't previously used a pump for this specific purpose then it can be difficult to recommend an exact model - additional factors such as bend in the pipes, friction etc. can contribute to what size pump you need. Overall, I would look at the total head amount (both suction height and discharge height) you require and then choose a pump that has a maximum head higher than that total head height number. Its good to choose a pump with comfortably more maximum head than total head amount you need to make sure still have sufficient water flow / pressure for your transfer application. Thanks

9 February 2016
For a relatively small pump (say in the region of 7 hp) doing flood irrigation duties in a tropical environment, where run time might be 2 days (virtually) continuously, would you recommend petrol or diesel? Maybe I should have asked this on your petrol vs. diesel page, but it's a pump!

My Generator Response
Hi Glen, thanks for your question. For running an engine (whether for a pump, generator, whatever) continuously for that sustained period, I'd suggest the diesel option. Diesel engines don’t have to work as hard as petrol engines to get the same power output, meanings the engine parts are under less stress. Also diesel fuel is self-lubricating which means the fuel delivery system should last longer than that of a petrol engine. The trade-off is that diesel engines are more expensive than petrol at the outset, but you'll likely experience lower cost of ownership over the life of your diesel pump. Hope that helps, Cheers - Steve

24 September 2015
A very useful article that breaks down all the different categories of water pumps and the different factors to judge the quality. Well written and nicely explained. This is a must read for anyone starting with pumps.

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