Water Pump Learning Centre.
Water Pump Learning Centre
Pump sizing, rainwater supply, mains boosting and troubleshooting — explained around the jobs homeowners actually need to solve.
Use our pump guides and interactive tools to work out required flow and head, choose between rainwater and mains boosting systems, compare external and submersible setups, diagnose pressure problems and understand the controls that keep a pump system working properly.
What Are You Trying to Work Out?
Choose the closest question and jump straight to the guide that owns that topic.
The most relevant guide will appear here.
Start With the Job, Then Choose the Pump
The easiest way to get pump selection wrong is to start with watts, horsepower or maximum flow. Start with the application, then calculate the flow and head the system actually needs.
Size the Duty
Work out required L/min and metres of head before comparing pump models.
Understand sizing → 2Match the Application
Rainwater, household pressure, harvesting and mains boosting need different pump setups.
Compare applications → 3Understand the Controls
Pressure tanks, electronic controllers, non-return valves and dry-run protection affect behaviour.
Learn the controls → 4Troubleshoot First
Diagnose pressure, priming, power and cycling problems before replacing a pump.
Find the fault →The 8 Water Pump Guides
Each guide owns a different research intent so the cluster stays useful without pages competing with each other.
What Size Water Pump Do I Need?
Calculate required flow and total head from target pressure, lift, pipe run and pipe size.
Open sizing calculator RAINWATER SELECTORRainwater Tank Pump Sizing Guide
Choose a pump for garden watering, irrigation, household fixtures or general tank-water supply.
Size a tank pump BOOSTER SELECTORMains Water Pressure Booster Pump Guide
Diagnose poor mains pressure and compare compact vs higher-capacity whole-home boosting.
Check mains boosting MAINS BACKUP GUIDERainwater Harvesting Pump Systems Explained
Understand automatic tank-water priority, mains backup and surface vs submersible RainBank-style systems.
Explore rain harvesting HOUSEHOLD DEMAND TOOLHousehold Water Pressure Pump Guide
Size tank-fed pressure for houses, sheds, granny flats and off-grid whole-home supply.
Size household pressure INSTALLATION COMPARISONSubmersible vs External Rainwater Pumps
Compare noise, servicing, priming, suction conditions, tank access and pump location.
Compare pump positions SYMPTOM CHECKERWater Pump Not Working?
Troubleshoot no start, no water, low pressure, loss of prime, tripping, noise, leaks and controller faults.
Troubleshoot pump faults SHORT-CYCLING CHECKERWhy Does My Water Pump Keep Turning On and Off?
Check leaks, pressure tanks, non-return valves, controller behaviour and pump oversizing.
Diagnose cyclingPump Sizing Basics: Flow, Pressure & Head
These smaller research questions belong on the Learning Centre because they support every pump guide without needing separate pages.
What Is Flow Rate?
Flow is the volume of water moving through the system, usually shown in litres per minute. More outlets operating at once require more flow.
What Is Water Pressure?
Pressure is the force available to move water through taps, showers and appliances. It may be shown in kPa, bar or PSI.
What Is Metres of Head?
Head is another way of expressing the energy a pump must provide. Roughly 9.81 kPa equals 1 metre of water head.
What Is a Duty Point?
The duty point is the flow the pump must deliver at the total head required by the installation, such as 50 L/min at 40 m head.
Why Maximum Flow Can Mislead
Maximum flow is generally measured at very low head. A real installation always has pressure, elevation and friction to overcome.
Why Maximum Head Can Mislead
Maximum head is normally reached when flow approaches zero. It does not tell you how much water the pump delivers under normal use.
The main sizing guide combines flow, target pressure, static lift, pipe length and pipe size to estimate the operating point you should compare against the manufacturer's pump curve.
Pressure Conversions Explained
| Pressure | Approx. Equivalent | Why It Matters |
|---|---|---|
| 100 kPa | 10.2 m head / 1.0 bar / 14.5 PSI | Useful as a basic conversion reference when reading pump curves. |
| 200 kPa | 20.4 m head / 2.0 bar / 29 PSI | Pressure head must still be added to elevation and friction. |
| 300 kPa | 30.6 m head / 3.0 bar / 43.5 PSI | A common example target when estimating household pressure duty. |
| 400 kPa | 40.8 m head / 4.0 bar / 58 PSI | Higher pressure requires more pump head at the same flow. |
| 500 kPa | 51.0 m head / 5.0 bar / 72.5 PSI | Actual plumbing pressure must suit the installation and controls. |
Which Pump Application Matches the Job?
| Application | Typical Job | Start Here |
|---|---|---|
| Rainwater pressure pump | Tank to garden, irrigation, house or general water supply | Rainwater Tank Pump Sizing Guide |
| Household pressure pump | Tank-fed houses, sheds, granny flats and off-grid supply | Household Water Pressure Pump Guide |
| Rainwater harvesting system | Tank water priority with automatic mains-water backup | Rainwater Harvesting Systems Explained |
| Mains pressure booster | Improving weak or inconsistent mains water pressure | Mains Water Pressure Booster Pump Guide |
| Submersible rainwater system | In-tank pumping where noise or external space matters | Submersible vs External Rainwater Pumps |
How Far Can a Water Pump Push Water?
Horizontal distance alone does not determine pump capability. Long pipe runs increase friction, and the amount of friction depends heavily on flow rate and internal pipe diameter.
Horizontal Distance
A pump can often move water a long horizontal distance if the pipe is correctly sized and the required flow is modest.
Vertical Lift
Every metre of vertical rise directly adds approximately one metre of static head to the pump duty.
Pipe Diameter
A small increase in pipe diameter can substantially reduce friction loss, especially at higher flows.
Water Pump Controls Explained
The pump creates the pressure and flow, but the controls determine when it starts, when it stops and how safely it behaves.
Electronic Pump Controller
Automatically starts the pump when flow or pressure demand is detected and stops it when demand ends, depending on controller design.
Pressure Switch
Uses cut-in and cut-out pressure settings to start and stop a pump, commonly with a pressure tank.
Pressure Tank / Accumulator
Stores a small amount of pressurised water so minor demand does not require an immediate pump start.
Non-Return Valve
Helps prevent water flowing backwards after the pump stops. A leaking valve can cause pressure loss and cycling.
Dry-Run Protection
Stops or protects the pump if the system detects insufficient water, helping reduce damage from running without adequate supply.
Variable-Speed Control
Adjusts motor speed to maintain more stable pressure across changing flow demand.
Self-Priming, Priming & Cavitation
What Does Self-Priming Mean?
A self-priming pump is designed to deal with some air in the suction line after correct initial setup, but it still needs suitable suction conditions and cannot overcome major air leaks.
Why Does a Pump Lose Prime?
Suction-side air leaks, a failed foot or non-return valve, low water level or water draining back from the suction line can cause loss of prime.
What Is Cavitation?
Cavitation can occur when suction conditions are poor enough for vapour bubbles to form and collapse inside the pump, often causing noise, vibration and reduced performance.
Common Water Pump Problems
Use the dedicated troubleshooting guide for broad pump faults and the short-cycling guide for frequent starting and stopping.
Water Pump Not Working?
Use the symptom checker for no start, no water, loss of prime, low pressure, tripping, noise, leaks and controller faults.
Open troubleshooting guide SHORT CYCLINGPump Keeps Turning On and Off
Check leaks, pressure tanks, drain-back, non-return valves, controllers and pump oversizing.
Open cycling guideExplore Water Pumps by Application
Finished researching? Move into the collection that matches the water source and job.
Water Pump Learning Centre FAQs
What size water pump do I need?
Size the pump from the required simultaneous flow and total head. Total head includes target pressure, vertical lift and pipe/friction losses.
What is the difference between pressure and head?
Pressure is commonly shown in kPa, bar or PSI, while pump head is shown in metres. Approximately 9.81 kPa equals one metre of water head.
How far can a water pump push water?
The answer depends on flow, pipe diameter, horizontal distance, vertical lift and fittings. Long horizontal runs mainly add friction, while vertical rise adds static head directly.
What is a pump duty point?
The duty point is the required flow at the required total head, such as 50 litres per minute at 40 metres head.
What is the difference between a rainwater pump and a mains booster?
A rainwater pump draws from a tank or stored-water source. A mains booster increases pressure in an existing mains water supply where the installation allows it.
Do I need a pressure tank?
Not every system requires one. Pressure tanks can reduce frequent starts and satisfy small water demands without immediately starting the pump, depending on the control arrangement.
What is dry-run protection?
Dry-run protection stops or protects the pump when insufficient water is detected, helping reduce damage from operating without adequate supply.
Why does a water pump lose prime?
Common causes include suction-side air leaks, a failed foot or non-return valve, poor suction layout or low source water level.
Why does my pump keep turning on and off?
Short cycling can be caused by leaks, a faulty or incorrectly charged pressure tank, a leaking non-return valve, control issues or an oversized pump.
Is a larger pump always better?
No. Oversizing can increase cost and contribute to cycling or pressure-control problems. The pump should be matched to the required duty point.
Work Out the Job First. Then Choose the Pump.
Use the Learning Centre to understand flow, pressure, head, controls and common faults, then move into the pump category that matches your actual water source and application.
