Well Pump Sizing Calculator
Calculate pump capacity and horsepower requirements
Well Information
Depth to water at rest
Water drop during pumping
From well test
System Requirements
Demand Calculation
Pump Requirements
Recommended Pump Size
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Required Flow Rate
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Total Dynamic Head (TDH)
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Pumping Level
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Friction Loss
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Pressure Head
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Pressure Tank Size
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Pump Setting Depth
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System notes will appear here.
TDH Formula
TDH = Pumping Level + Pressure Head + Friction Loss + Elevation
Pumping Level = Static Level + Drawdown
Pressure Head = PSI x 2.31 ft/PSI
Friction Loss = Based on pipe size, length, GPM
Elevation = Height above well head
Pump Selection Guide
| Pump Type | Max Depth | Typical HP | Best For |
|---|---|---|---|
| Jet (Shallow) | 25 ft | 1/2 - 1 HP | Shallow wells, easy access |
| Jet (Deep) | 90 ft | 1/2 - 1-1/2 HP | Deep wells, above-ground pump |
| Submersible | 400+ ft | 1/2 - 5 HP | Deep wells, most reliable |
| Submersible (4") | 1000+ ft | 3/4 - 25 HP | Commercial, high capacity |
Friction Loss Reference (ft per 100 ft of pipe)
| GPM | 3/4" | 1" | 1-1/4" | 1-1/2" | 2" |
|---|---|---|---|---|---|
| 5 | 3.8 | 1.1 | 0.3 | 0.1 | 0.05 |
| 10 | 13.5 | 3.8 | 1.1 | 0.5 | 0.15 |
| 15 | 28.0 | 8.0 | 2.3 | 1.0 | 0.3 |
| 20 | 47.0 | 13.5 | 3.8 | 1.7 | 0.5 |
| 30 | -- | 28.0 | 8.0 | 3.5 | 1.1 |
Flow Rate Guidelines
Residential
- 1-2 bathroom: 6-10 GPM
- 2-3 bathroom: 10-15 GPM
- 3-4 bathroom: 15-20 GPM
- Irrigation add: 5-10 GPM
Pressure Tank
- Minimum: 1 gal/GPM
- Recommended: 1.5 gal/GPM
- Standard sizes: 20, 32, 44, 86 gal
- Pre-charge: 2 PSI below cut-in
Pump Setting
- 10-20 ft above bottom
- Below pumping level
- Above motor for cooling
- Check pump curve
Wire Sizing
- 3-wire: Control box
- 2-wire: Built-in controls
- Size per NEC 430
- Voltage drop <5%