A water pump's maximum flow and maximum head are usually different points on its performance curve. Do not assume the advertised maximum flow is available at the advertised maximum lifting height.
Describe the job first
Record the water source, required destination height, pipe route and intended use. Check whether the pump is designed for clean water, specified dirty water or another liquid. Particle limits and material compatibility matter independently of motor power.
| Specification | What to compare |
|---|---|
| Flow curve | Expected flow at the actual operating head |
| Inlet and outlet | Connection sizes and the approved pipe arrangement |
| Suction conditions | Priming and positioning requirements where applicable |
| Duty and controls | Permitted operating pattern and protection features |
Include the whole system
Vertical lift, pipe length, fittings and restrictions affect the operating point. Use the manufacturer's sizing guidance or obtain suitable technical advice rather than choosing only by watts. Confirm power and installation requirements before purchase. A pump for a pond or garden is not automatically suitable for drinking water, chemicals or flood conditions. Follow the exact product's permitted use and electrical safety instructions. Clear application details are the best starting point for selecting a pump that performs the required job.