Pressure and Flow

When planning an irrigation system, it’s important to know both your flow rate and pressure. These measurements determine how much water is available and how effectively your system will run.

What is Flow Rate?

Flow rate is the amount of water expelled from your source over time, usually measured in litres per minute (L/min) or litres per hour (L/h).

• Why it matters: Flow rate controls how many sprinklers, sprayers, or drippers can run in a single zone. Higher flow rates allow more devices per zone, while lower flow rates may require splitting into multiple zones.

• Tip: Only use up to 70% of your available flow rate to account for natural fluctuations.

How to Measure Flow Rate (Bucket Test)

You can measure flow rate easily with a bucket and a timer:

1. Use a bucket of known size (ideally 10 litres).

2. Place it under your garden tap or outlet.

3. Turn the tap on fully and start timing.

4. Stop when the bucket is full and record the time in seconds.

5. Use this formula:

Flow rate (L/min) = (Bucket size in litres ÷ Time in seconds) × 60

Example: A 10-litre bucket fills in 25 seconds →
10 ÷ 25 = 0.4 → 0.4 × 60 = 24 L/min

Alternatively, you can use a flow cup for a quick measurement.

What is Pressure?

Pressure is the force of water inside your system, measured in BAR or PSI.

• Static pressure: The force when water is at rest. This is the common measurement provided.

• Dynamic pressure: The force when water is flowing. Measuring this requires specialist tools, so we don’t request it from customers.

How to measure: 

1. Attach a pressure gauge to your tap.

2. Turn the Tap on fully.

3. Read the result off the gauge. 

• Tip: Most garden taps have a 3/4" thread size, so ensure your gauge has this size thread.