Pump power (HP and kW) to lift water to your roof tank, including pipe friction.
How this works
Total head = suction lift + height to tank + pipe friction (Hazen-Williams, C = 150 for PVC, plus 20% for bends). Power = 9.81 x flow (m³/s) x head (m) / efficiency, with about 45% efficiency for small home pumps. 1 HP = 746 W.
Questions people ask
How do I use the Water Pump Size tool?
Fill in the fields, starting with “Suction lift (water level below pump)”, “Height from pump to tank inlet” and “Total pipe length”, and change any other options that match your home. The answer, a drawing and practical tips update as you type, and the Copy link button saves your numbers in a link you can share.
Is the Water Pump Size tool free?
Yes. The Water Pump Size tool is free, with no sign-up, and works on phones, tablets and computers. The results are estimates to help you plan, so check with a qualified professional before structural, electrical, gas or plumbing work.