We sat down with our in-house water pumps expert, Garth Rudlin for a quick chat about water pumps. We put together a list of the most common questions we get asked by our customers and builders.
Q. How does a water pump work?
A. Since our civilization, humans have needed to move water from one point to another. Prior to electricity, this was done with hand pumps and manual labor. Since the invention of electricity, we have used water pumps. In general a pump uses a motor (energy) and an impeller to force water through a discharge port. Because of the impeller and diffuser pathways, the water leaves the discharge port with a higher velocity and can be moved along pipe work or hoses into your domestic home or garden.
Q. How many types of water pumps are there?
A. Whilst I can’t tell you how many different types of pumps are out there in the market, I can tell you there must be over twenty different types of pumps. Most people don’t realize that every day they are using pumps without their knowledge. There are pumps in cars for your radiator, fuel injecting pumps, in your fridge and air-conditioners. Most people think of water pumps as your traditional garden pump that you use to water your garden or domestic water pumps for your home. Domestic Water Pumps this makes up the majority of our sales here at ASC Water Tanks, by no means are they the majority across all pump sales.
On top of the traditional water pumps that are pictured above, ASC Water Tanks also carry submersible water pumps used for domestic applications, that is submersible pressure pumps with inbuild controllers for running a household. On top of that, we carry a huge range of submersible drainage and sewerage pumps for domestic, commercial and industrial applications.
There are also domestic changeover pumps also known as Tank-2-Mains switch pumps. These mains switch pumps use water from your water tank to feed your home. When the tank runs empty, the pump will automatically switch to Mains Water Supply, to ensure your household always has water. Different manufacturers have their own proprietary means to switch between tank and mains water supply and there are better systems than others, and as such you do get price variations. In our opinion, floated systems are the best however they are also the more expensive systems.
Q. How much does it cost for a water pump?
A. At ASC Water Tanks, we try to match the right water pump to the application within a budget. We pride ourselves on having the largest range of water pumps in Australia, and we work with Australia’s best known brands. This, coupled with the best prices for water pumps online, we should be able to match a pump to your needs. Generally speaking when you are after a small garden pump, you would be paying around $200-$300. A domestic household pump for a family of four would set you back anywhere between $350 and $700. For the latest and greatest in technology and energy efficient domestic pumps, you would look at a Variable Speed Pump. These pumps are more expensive upfront, but over the long term of your pumps lift will be the cheapest as they consume the least amount of energy. Variable speed pumps range from around $800 to $2500 in a domestic application.
Q. How does an electric domestic water pump work?
A. Much of the mechanics in an electric water pump is in the motor and the impeller. The impeller is a fixed item like the blades of a fan. There are varying sizes of impellers in a domestic pump, along with vein sizes and also the number of impellers in a pump. These factors vary the flow rate and pressure in your pump. You then have an electric motor. In fixed speed pumps, which make up around 95% of our sales, your motor spins at 2900rpm. This fixed speed means that as you make changes to the impeller specifications, how need a larger motor to be able to ensure you can spin the motor at 2900rpm. This is why we have varying power consumption on water pumps.
Q. How much does it cost to replace a water pump?
A. There are two costs involved with replacing a water pump. Your initial costs will be to find a suitable replacement and the secondary cost is finding a plumber or suitable tradesperson to disconnect the old pump and reconnect the new water pump. Consumers always look at replacing the whole pump, but many of our trusted brands, carry spare parts. ASC Water Tanks encourages customers to look at repairing water pumps before replacing them. Not only can you save a lot of money, but you are also being environmentally conscious. In cases, where your existing pump is too old, and spares are no longer available or the cost / benefit does not make sense, then ASC has the best pricing available in Australia’s famous brands including Davey Pumps and Onga Pumps. It will depend on your application and needs. When replacing an existing pump with very little changes in your pipework, we advise our customers not to pay more than around $200 for labour.
Q. Where can I buy a Water Pump?
A. We are based in Hallam Victoria for all our Melbourne customers who want to come in store for advice and buy a water pump. We stock over 2000 water pumps in our warehouse from all makes and manufacturers. For all our other customers, we have the most comprehensive range of pumps online with technical data sheets and information required to make an informed choice. We are always available by phone or email if you have any questions on 03 8795 7715.
Q. Where can I use a water pressure pump?
A. A pressure pump can used to flush toilets in a home and be pumped to gardens and used to irrigate via sprinklers or hoses. Many pumps are used for watering livestock by pumping water to gravity feed tanks or directly to water troughs from water tanks, dams and rivers. Pressure pumps are also commonly used to boost mains water pressure for areas where there is low mains water pressure. In this case, the water pump is directly connected to the mains water supply, and is then fed to your domestic household.
Q. Which type of water pump is best for domestic use?
A. A pressure pump is the most popular pump used for domestic application. They have an automatic pressure controller, which means the pump turns on and off on demand. All of our pressure pumps systems also have run dry protection. This protects the pump in cases where the tank or water source runs dry and turns off your water pump automatically to stop the motor burning out from running continuously.
In terms of the best type of pump for a home or domestic use, we highly recommend and push customers down the path of variable speed drive pumps. These pumps only turn on as much power as they need based on your demand. That means, if you are running just one tap, the pump will only turn on as much power as required to run that one tap. In variable speed pumps, unlike fixed speed pumps, the motor can vary the operating RPM. As an example, a variable speed pump that is rated at 1.5kW might only use 0.2kW to flush a toilet and 0.45kW to run a shower. As more taps and showers turn on at once, the pumps motor speed increases, which increases the power use, which in turn increases the pumps flow rate.
DAB Esybox Variable Speed 
Davey Dynadrive Variable Speed 
Grundfos Scala2 Variable Speed
Q. Do you need a pump for a water tank?
A. Without a water pump the water in the tank will only have gravity to push the water out of the tank. This is okay for soaker hose applications and for filling a bucket, but not suitable for watering a lawn or for garden use. Without the added energy from a pump, the water cannot push througoto sprinklers or a hose nozzle.
Q. What size water pump do I need?
A. Sizing a water pump would entirely depend on the application. Every application, be it domestic household, garden watering, broad acre irrigation, toilet flushing, or pressure boosting has a range of pumps that will work within those parameters. Without the application requirements it would be tricky to say. Manufactures give a broad range of pumps that work for domestic application, however these are just a guide, and we recommend sizing the pump up specific to your home and your application. Below is chart by Davey Water Pumps that lists home type, pressure requirements, flow rate requirements and then pumps that would be suitable.
ASC Water Tanks have been supplying Australian homes with rainwater tanks and pumps since 2007. We sell top-grade Australian Made water tanks to support our economy and to deliver a superior product to our customers and have industry experts able to assist in your next project.
To discuss your next water pump set up for your rainwater harvesting system at home or irrigation system, contact us here or give us a call on 03 8795 7715.
Article Co-Authored By: Garth Rudlin (Pump Specialist) & Anant Yuvarajah (Director)