Test and measure your pump
A bucket, a stopwatch and a multimeter: measure your own pump curve like a pump factory does.
⏱ 7 min
- Everyday comparisonStep 1 of 6
A report card for your pump
A runner doesn’t just say “I’m fast” — they time themselves. Engineers do the same with pumps: they measure flow, head and power, and draw the curve.
You can do it at home with things you already have.
- ExplainedStep 2 of 6
Measuring flow and head
Flow: time how long it takes to fill a jug of known size. 1 litre in 10 seconds = 6 L/min.
Head: lift the end of the outlet tube above the water surface in the tub. That height is the head. Raise it until the water just stops coming out: that is your shut-off head.
- Try itStep 3 of 6
Build your curve
Set a hose height, let the jug fill, then record the point. Do it for several heights — from 0 up to where the flow stops — and your pump curve appears on the right.
Challenge: Record at least five points. At which height is the power going into the water the greatest?
- ExplainedStep 4 of 6
Measuring power and efficiency
With a , measure the supply voltage and the current: watts = volts × amps. That is the power going in.
The power reaching the water is ρ·g·Q·H (about 0.16 W for 1 L/min at 1 m). Divide the two and you have your efficiency.
- ExplainedStep 5 of 6
Don’t be shocked by the number
Small hobby pumps often reach only a few percent efficiency. Tiny motors waste a lot, seals rub, and small channels have lots of friction.
Industrial pumps reach 80–90% because every loss you met in Module 6 has been fought for decades.
- The impeller connectionStep 6 of 6
Improve, one change at a time
Change one thing — the gap, the number of vanes, the outlet angle — reprint, and measure again. Compare the curves. That is exactly how pump makers improve their designs.
You now know the whole journey: from what a fluid is, to designing, building and testing your own impeller. One step left: the final exam.
📌 Remember this
Measure flow with a jug and a stopwatch, head by raising the outlet, and power with volts × amps. Plot flow against head to get your own pump curve, then improve one thing at a time.