Submersible vs Surface Bore Pumps | How to Size the Right Pump for Your Australian Property

Introduction

If you’re managing a bore on your Aussie property, one of the biggest mistakes you can make is getting the pump sizing wrong. Whether you choose a submersible or a surface bore pump, the key is sizing it properly so you don’t waste money, suffer low pressure or damage the equipment. In Australia’s varied terrain and water-table conditions, knowing how to size a bore pump becomes critical. In this post we’ll walk you through everything you need: bore pump sizing, flow rate, bore depth, bore water pressure, and how the choice between submersible vs surface bore pumps plays out.

1. The Basics of Bore Pump Sizing

To size a bore pump correctly you need to understand three critical factors: the bore depth, the flow rate you need, and the pressure or head you must overcome. Simply picking “what size bore pump do I need” without those metrics is asking for trouble.

• Bore depth & static/dynamic water level: how deep is the bore and how far below the surface is the pump water level.
  
  

• Flow rate (litres per minute or litres per hour) – this tells you the volume of water you require from the bore.
  
  

• Bore water pressure / head: the vertical lift plus any friction losses and distance the water must travel. Reference sources in Australia show flow charts and head curves for bore pumps.

For example, one Australian guide says you must determine how much water you want, what size bore casing you have, and what head pressure is required.

2. Submersible vs Surface Bore Pumps – What’s the Difference?

Submersible bore pump: the pump sits down in the bore, submerged in the water. Advantages: better suited for deep bores, less suction lift issues, often more efficient for underground water supply.
Surface bore pump: the pump is mounted above ground and draws water up from the bore. Advantages: easier access for maintenance, simpler installation in shallow bores, often lower upfront cost.

In Australia, terrain and bore conditions vary widely: coastal regions, inland farmland, remote properties. Choosing between submersible vs surface bore pump often depends on bore depth, casing diameter, and water table behaviour.

One vendor notes that for submersible bore pumps you first determine the size and flow (and bore size), then select pump motor size accordingly.

3. How to Size a Bore Pump (Step-by-Step)

Here’s a step-by-step method you can follow for your Australian bore:

Step A – Determine Required Flow Rate
Calculate how much water you’ll need. For instance: garden irrigation, livestock, household use. Pick litres per minute (LPM) or litres per hour (LPH). Use a “bore pump size chart” or flow chart to select a pump that meets or slightly exceeds that flow. 

Step B – Calculate Total Head / Bore Water Pressure

Total head = vertical lift + friction losses in the pipe + required service pressure. Although many guides use imperial units (feet & psi), convert to metres and kilopascals for Australia. One Australian pump sizing guide lists vertical suction lift rules, noting practical suction lift of ~6.7 m at sea level. 

Step C – Match Pump to Bore Size and Power (horsepower guide)

Once flow and head are known, reference a chart to pick the correct pump size (and horsepower). For example: if your bore casing is 4″, flow is ~60 L/min and head is ~65 m, you’ll choose a certain pump.

Step D – Check Bore Casing & Depth
Your bore diameter limits pump size: e.g., a 4″ casing can only accept certain pump dimensions. Also check if the water level will drop under load (dynamic draw-down) which affects real flow.

Step E – Final Adjustment for Surface vs Submersible
If you have a shallow bore and low head requirement, a surface bore pump might suffice and be easier to maintain. If deep bore and high head/distance, go submersible.

4. A Practical Australian Example

Imagine you have a bore on a 40 m deep property with casing size 100 mm (~4″). You demand ~80 L/min to service irrigation and household use. The delivery point is 50 m away horizontally and the tank is 10 m higher than the bore head. Calculate head: 10 m lift + friction loss (say 5 m) = ~15 m head. Using a flow chart you select a pump capable of 80 L/min @ 15 m head. You check casing size to ensure pump fits. Decide between surface (since head low) or submersible depending on how stable the water level is. If the water level drops to 20 m under load, you might lean submersible to avoid suction issues.

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Here are keywords (and long-tails) you’ll want to weave naturally:

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You can also include variants like “bore pump size chart Australia”, “Australian bore pump sizing guide”, “surface bore pump sizing Australia”.

6. Five Common Questions Australian Users Ask

Q1: How do I know what size bore pump I need for my rural property?
You calculate your required flow rate and head (bore depth + delivery point height + friction loss) then use a bore pump size chart relevant to Australian sizes and casing diameters.

Q2: Can I use a surface bore pump if my bore is deep?
It depends. If the borehead to water level distance is small and suction lift isn’t extreme, yes. But for deep bores or large vertical lift, a submersible pump is almost always the better option to avoid cavitation and loss of pressure.

Q3: What role does bore depth play in sizing the pump?
Bore depth dictates how far the water must be lifted (head). If water level drops under load, your effective head increases and your pump must be sized accordingly. Bore depth also influences the casing diameter and therefore the size of pump you can install.

Q4: How much horsepower do I need for a bore pump in Australia?
Horsepower (or kilowatt rating) ties to the required flow and head. Use the calculated flow rate and head, consult a pump manufacturer’s horsepower guide, and ensure the pump motor is not oversized (which wastes energy) or undersized (which fails to deliver).

Q5: What is the difference between a progressive cavity water pump and a standard bore pump?
A progressive cavity pump uses a rotor and stator design to move water or slurry with consistent flow, even under variable loads and depths. In bore situations with sandy or variable water quality, such pumps may handle heavy loads better than standard centrifugal pumps. But they may cost more and require different maintenance.

7. Final Tips for Australian Property Owners

• Always test your bore: measure static and pumping water levels, flow rate under test, and check casing size. One Australian installer emphasises testing before sizing.
  
  

• Use a pump sizing calculator or chart specific for submersible vs surface bore pumps. Many Australian suppliers offer these tools.
  
  

• Factor total distance (horizontal and vertical) and pipe diameter when calculating friction loss.
  
  

• Choose a pump with a little margin (e.g., 10-20%) above your calculated flow/head to allow for future expansion, but avoid huge oversizing which reduces efficiency.
  
  

• For surface pumps, ensure minimal suction lift (in Aussie terms, keep the pump near the water source) to avoid performance issues.
  
  

• For submersible pumps, monitor water level drop under load (draw-down) and ensure the pump stays submerged at all times.
  
  

• Regular maintenance matters: cleaning filters/screens, monitoring motor current, keeping power supply stable.
  
  

• When in doubt, engage a local bore pump specialist who knows Australian conditions (red soil, remote sites, water table seasons) rather than relying solely on generic overseas specs.

For more detailed pump sizing services and support, visit Pumptastic and feel free to Contact us for tailored advice.