Pump Efficiency & Wire-to-Water & Energy per m³
Tests borewell
Enter flow, head and electrical input power to get the wire-to-water efficiency, the hydraulic power and the energy used per cubic metre of water.
Enter your pump
Next: if below ~40%, check for a worn impeller, throttled valve, oversized motor, low voltage or a clogged foot valve; a right-sized efficient set can halve the energy per m³.
Hydraulic kW = ρgQH; input power should be the real electrical draw (kW), not just the nameplate rating.
Pump efficiency — key facts
- Efficiency
- hydraulic out ÷ input × 100
- Hydraulic kW
- ρgQH ÷ 1e6 (Q L/s, H m)
- Poor
- < 25%
- Good
- 40–55%
- Excellent
- ≥ 55%
- Energy/m³
- input kW ÷ flow (m³/h)
- Common loss
- worn impeller, throttled valve
- Privacy
- Runs in your browser; nothing uploaded
Every inefficient hour is electricity poured away
A pump that drinks 16 kW from the wire but only puts 8 kW into the water is throwing away half of everything you pay for — and it does that every single hour it runs. Wire-to-water efficiency is the one number that exposes this: useful hydraulic power out over electrical power in. Because irrigation pumps run for so many hours, even a modest gain in efficiency translates into real money saved across a season, and a poor result is a clear signal to service or resize before the next bill.
This tool gives the efficiency percent, the hydraulic power, the input power and the energy used per cubic metre from your flow, head and electrical input. Use it to band your pump from poor to excellent, hunt down causes like a worn impeller, throttled valve, oversized motor, low voltage or clogged foot valve, and track the kWh per m³ over time. Pair it with the Irrigation Pump Power, Solar Pump Sizing and Solar Pump ROI tools to plan and cost an efficient pumping system.
Catch the waste
See the percent of power that reaches water.
Band the pump
Poor, fair, good or excellent at a glance.
Cost the water
kWh used for every cubic metre pumped.
Target repairs
Spot worn impellers, valves and voltage.
Frequently Asked Questions
What is pump (wire-to-water) efficiency?+
Wire-to-water efficiency is the useful hydraulic power the pump puts into the water divided by the electrical power drawn from the wire, expressed as a percent. It captures the whole system — motor and pump together — so it tells you how much of the electricity you pay for actually ends up lifting and moving water.
How is pump efficiency calculated?+
Efficiency % = hydraulic power out ÷ electrical power in × 100. The hydraulic power in kW is ρgQH ÷ 1,000,000 with flow Q in litres per second and head H in metres. So a pump delivering 8 kW of hydraulic power while drawing 16 kW from the wire is running at 50% efficiency.
What is hydraulic power?+
Hydraulic power is the useful power the pump adds to the water to lift it against the head at the given flow. In kilowatts it is ρgQH ÷ 1,000,000, where ρ is water density, g is gravity, Q is flow in L/s and H is head in metres. It is the numerator of the efficiency calculation.
What efficiency should my pump have?+
As a guide for wire-to-water efficiency: under 25% is poor, 25–40% is fair, 40–55% is good, and 55% or above is excellent. Many neglected farm pumps sit well below their potential, so even a fair result usually means there is energy and money to be saved by servicing or resizing.
Why does low efficiency cost so much?+
A pump that runs for hours every irrigation turns wasted efficiency directly into wasted electricity bills, season after season. Lifting the same water at a higher efficiency cuts the input kW and the units consumed for every cubic metre, so improving a heavily used pump often pays back its repair cost quickly.
What causes low pump efficiency?+
Common culprits are a worn or eroded impeller, a partly throttled delivery valve, an oversized motor running off its best point, low supply voltage straining the motor, and a clogged foot valve or strainer restricting flow. Operating far from the pump's design head and flow also drops efficiency sharply.
What is energy per cubic metre?+
Energy per m³ = input power in kW ÷ flow in m³ per hour, giving the kWh used to pump each cubic metre of water. It is the most useful single number for comparing pumps and tracking a pump over time, because it ties electricity directly to the water delivered regardless of run hours.
How do I measure the input power?+
Read the electrical input from an energy meter or clamp meter at the motor — power in kW, or volts and amps with the power factor. Measure flow with a flow meter or by timing a known volume, and the head from the pressure gauge or the lift plus friction. Accurate inputs give an accurate efficiency.
Can I improve my pump's efficiency?+
Often yes — replace a worn impeller, open up a throttled valve and remove restrictions, clean the foot valve and strainer, correct low voltage, and right-size the motor to the duty. If the pump is simply the wrong size for the head and flow, replacing it with a correctly matched unit usually gives the biggest gain.
Are these figures exact?+
They are solid engineering estimates from your inputs. Real efficiency varies with the operating point, water temperature, wear and measurement accuracy, so use the result to spot a problem and prioritise action, then confirm with careful field measurements before investing in a repair or replacement.