Free MEIC engineering tool
Submersible Pump Selector: Flow, Head and Power
Enter the water level, required flow and pipe size to get total head, friction loss and the suggested motor kW — using the same equations we design with, plus a warning if water velocity is too high.
The default 55% efficiency is conservative for mid-size submersible pumps. Lower it for old pumps or harsh duty.
Estimated result
- Total head
- 89.6 م
- Friction loss
- 4.44 م
- Pipe velocity
- 1.70 م/ث
- Hydraulic power
- 2.93 kW
- Shaft power
- 5.33 kW
- Suggested motor
- 7.5 kW
- Pump size
- 6"
Velocity above 1.5 m/s — increase the pipe size to cut friction and wear.
The equations behind the result
Total head
H = Hs + S + Hd + hf + HpStatic level + drawdown + delivery height + friction + pressure head.
Friction (Hazen-Williams)
hf = 10.67 · L · Q^1.852 / (C^1.852 · D^4.87)With roughness C = 140 for plastic and new steel pipe.
Power
P = 9.81 · Q · H / (3600 · η)Shaft power; a 15% margin is added for the motor rating.
Note: this is a preliminary engineering estimate for pump selection — not a quotation, and no substitute for measuring the actual static level and yield on site. The final choice follows the manufacturer's pump curve.
Frequently asked questions
How is total head calculated for a submersible pump?
Total head = static water level + drawdown while pumping + delivery height + pipe friction loss + the head equivalent of the required outlet pressure (1 bar ≈ 10.2 m). That sum is the head the pump actually lifts, not the borehole depth alone.
What pump power do I need for a 60 m well?
Power follows the flow rate, not the depth alone. A well with a 60 m static level delivering 12 m³/h needs roughly 11 kW after friction and efficiency, while the same well at 5 m³/h needs about 5 kW. Enter your own numbers in the calculator above.
When do I choose a 4-inch versus a 6-inch pump?
It depends on the casing diameter and the flow. A 4-inch cased well takes a 4-inch pump, typically up to about 5 m³/h. Higher flows need a wider well and a 6-inch or larger pump. Forcing a large pump into a tight well causes rapid wear and motor overheating.
Why does friction rise so fast in a small pipe?
Because the loss varies inversely with diameter to the power 4.87: halving the diameter multiplies the loss by more than 25 at the same flow. Keep water velocity under 1.5 m/s — the calculator warns you automatically when it is exceeded.
Need a real measurement and installation?
MEIC drills wells and installs submersible pumps, control panels and maintenance across Riyadh. Send the calculator result on WhatsApp or call 0554097005.