1. Pump the Bore Continuously Until It Stabilises

You cannot measure flow rate from the first few minutes of pumping. Australian bores often draw down initially, then stabilise.

Run the pump continuously for 60 minutes. 
If the flow reduces significantly during the hour, your bore yield is lower than you think.

2. Use the Container-Fill Method (Accurate Enough for Pump Sizing)

Forget overly complicated formulas unless you're in hydrogeology. For household and farming pump sizing, this approach is reliable:

• Use a 20L container (or larger).
  
• Time how many seconds it takes to fill.
  
• Convert:
  

Flow rate (L/min) = (Container volume ÷ seconds to fill) × 60

Repeat three times to get a stable average.

3. Record Static Water Level and Pumping Water Level

Bore depth alone is useless for pump choice what matters is the water’s behaviour under load.

Measure:

• Static water level (before pumping)
  
• Pumping water level (after 60 min of pumping)
  
  

These numbers determine the lift requirement, which influences pump horsepower selection.

4. Calculate Drawdown and Safe Pumping Limits

Drawdown = static water level – pumping water level.

A bore with heavy drawdown may need a smaller pump or a progressive cavity water pump to avoid over-extraction.

5. Match Flow Rate to a Bore Pump Size Chart

Once you have flow rate + lift requirements, you can compare against a bore pump size chart to determine:

• Pump stages
• Horsepower
• Optimal water output
• Suitable pump diameter
  
  

This is the point where people either get it right or set themselves up for years of frustration.

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Common Questions Australians Ask About Bore Flow Rate

1. What size bore pump do I need for my property?

It depends on the measured flow rate, bore depth, and required pressure. Anyone giving a generic answer is guessing.

2. How deep does a bore pump need to sit?

Deeper is not always better. It must sit below pumping water level but above the bore bottom to avoid silt damage.

3. Is higher horsepower always better?

No. Oversizing creates excessive drawdown and shortens pump life. Use a bore pump horsepower guide matched to your actual flow rate.

4. Why does my bore water pressure fluctuate?

Usually caused by poor pump sizing, variable flow rate, or using a pump curve that doesn’t match the bore yield.

5. When should I choose a progressive cavity water pump?

When your bore has low yield but stable water quality. They’re ideal for slow-producing Australian bores that can’t support high flow.

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How Flow Rate Connects to Bore Pump Sizing (The Part Everyone Skips)

Most Australians rush into buying a pump based on price or brand. That’s the fastest path to pump failure.

Here's the non-negotiable reality:

Your pump must stay below the bore’s safe long-term yield.
If your bore produces 25 L/min and you install a pump rated for 60 L/min, it will:

• suck the bore dry
  
• run hot
  
• cavitate
  
• die early
  

This is why the flow measurement is step one, not a “nice to have”.

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Example Flow-to-Pump Guidelines

These are not substitutes for a full pump curve, but they help you understand the logic:

• 10–20 L/min → small domestic submersible or progressive cavity water pump
  
• 20–40 L/min → standard household submersible, moderate horsepower
  
• 40–80 L/min → rural properties, irrigation setups
  
• 80+ L/min → high-demand agricultural systems
  
  

This is why the question “what size bore pump do I need?” is impossible to answer without measurements. Learn more in our Bore Pumps.

If you want accurate pump selection or a tailored recommendation for your bore, visit Pumptastic.

For direct assistance or technical support, head to Contact us.