Pumping Water  Required Horsepower
Horsepower required to pump water.
Energy imparted to water by the pump is called water horsepower  and can be calculated as
P_{whp} = q h SG / (3960 μ) (1)
where
P_{whp} = water horsepower (hp)
q = flow (gal/min)
h = head (ft)
SG = 1 for water Specific Gravity
μ = pump efficiency (decimal value)
Horsepower can also be calculated as:
P_{whp} = q dp / (1715 μ) (2)
where
P_{whp} = water horsepower (hp)
dp = delivered pressure (psi)
Example  Horsepower Required to Pump Water
20 gallons of water per minute is elevated 20 ft. The horsepower required (ex. friction loss in piping and efficiency = 1.0) can be calculated as
P_{whp} = (20 gpm) (20 ft) (1) / (3960 (1.0))
= 0.10 hp
Power required to pump water at 60^{o}F with ideal pump efficiency 1.0:
Power Required to Pump Water (hp)  

Volume Flow (gpm)  Height (ft)  
5  10  15  20  25  30  35  40  50  
5  0.00631  0.0126  0.0189  0.0253  0.0316  0.0379  0.0442  0.0505  0.0631 
10  0.0126  0.0253  0.0379  0.0505  0.0631  0.0758  0.0884  0.101  0.126 
15  0.0189  0.0379  0.0568  0.0758  0.0947  0.114  0.133  0.152  0.189 
20  0.0253  0.0505  0.0758  0.101  0.126  0.152  0.177  0.202  0.253 
25  0.0316  0.0631  0.0947  0.126  0.158  0.189  0.221  0.253  0.316 
30  0.0379  0.0758  0.114  0.152  0.189  0.227  0.265  0.303  0.379 
35  0.0442  0.0884  0.133  0.177  0.221  0.265  0.309  0.354  0.442 
40  0.0505  0.101  0.152  0.202  0.253  0.303  0.354  0.404  0.505 
45  0.0568  0.114  0.170  0.227  0.284  0.341  0.398  0.455  0.568 
50  0.0631  0.126  0.189  0.253  0.316  0.379  0.442  0.505  0.631 
60  0.0758  0.152  0.227  0.303  0.379  0.455  0.530  0.606  0.758 
70  0.0884  0.177  0.265  0.354  0.442  0.530  0.619  0.707  0.884 
80  0.101  0.202  0.303  0.404  0.505  0.606  0.707  0.808  1.01 
90  0.114  0.227  0.341  0.455  0.568  0.682  0.795  0.909  1.14 
100  0.126  0.253  0.379  0.505  0.631  0.758  0.884  1.01  1.26 
Note! Individual pump curves should always be used for exact calculations.
Power Consumption in Metric Units
The power consumption for pumping water can be expressed in metric units as
P = q h ρ / (6116 10^{3} μ) (3)
where
P = power (kW)
q = flow (liter/min)
h = head (m)
ρ = density (kg/m^{3}) (water 1000 kg/m^{3})
μ = pump efficiency (decimal value)
Example  Power Required to Pump Water
The power required to pump 100 l/min water an elevation of 10 m (ex. friction loss in piping and efficiency = 1.0) can be calculated as
P = (100 liter/min) (10 m) (1000 kg/m^{3}) / (6116 10^{3} (1.0))
= 0.16 kW
Related Topics

Pumps
Piping systems and pumps  centrifugal pumps, displacement pumps  cavitation, viscosity, head and pressure, power consumption and more.
Related Documents

Centrifugal Pumps
An introduction to Centrifugal Pumps. 
Efficiency in Pumps or Fans
The overall pump and fan efficiency is the ratio power gained by the fluid to the shaft power supplied. 
Hydropower
Power potential vs. head and flow rate. 
Positive Displacement Pumps
Introduction tutorial to positive displacement pumps basic operating principles. 
Power
Power is the rate at which work is done or energy converted. 
Power Gained by Fluid from Pump or Fan
Calculate the power gained by fluid from an operating pump or fan. 
Pump Power Calculator
Calculate pumps hydraulic and shaft power. 
Pumping Water  Energy Cost Calculator
Calculate the energy cost of pumping water. 
Pumps  Affinity Laws
Turbo machines affinity laws can be used to calculate volume capacity, head or power consumption in centrifugal pumps when changing speed or wheel diameters. 
Pumps  Head vs. Pressure
Converting head (ft or m) to pressure (psi or bar, kg/cm^{2}) and vice versa. 
Pumps  NPSH (Net Positive Suction Head)
An introduction to pumps and the Net Positive Suction Head (NPSH). 
Pumps  Parallel vs. Serial Arrangement
Adding head and flowrate for pumps arranged in parallel vs. serial. 
Pumps, Fans and Turbines  Horsepower
British Horse Power as used for pumps, fans and turbines  and how to convert to other units. 
Turbo Machines  Specific Work done by Pumps, Compressors or Fans
Calculate specific work done by pumps, fans, compressors or turbines. 
Water Pump Calculator
Water pump calculations.