Lake-Fed Sprinkler Pump Sizing: 3/4 HP Jet Pump for 3 Rotors at 3 GPM

Reviving Lake-Fed System: Pump Selection for 3 Rotors, 40 ft Suction, 15 ft Lift

1.5" PVC suction (40 ft, 5 ft lift), 1" poly discharge (100 ft, 15 ft lift), three 3.0 GPM rotors. 3/4 HP sprinkler pump failed (low pressure).

Pump Type Clarification

"Jet pump" just has an extra port (plugged for sprinklers). Use self-priming centrifugal or jet pump—same performance.

Target: 45 PSI at Pump Discharge

• 3 rotors × 3 GPM = 9 GPM demand.
• Need pump curve: 9 GPM at 45 PSI (104 ft head).
• 3/4 HP may be undersized for that head + friction.
• 1 HP self-priming centrifugal gives margin for expansion.

Nozzle Adjustment Alternative

If pump maxes at 7 GPM @ 45 PSI, use 2.5 GPM nozzles (7.5 GPM total). Better coverage than 3 GPM at low pressure.

Impact Sprinklers Won't Help

Same pressure needs. Low pressure = poor distribution (donut patterns).

Next Step

Reply for specific pump model recommendations (Berkeley, Goulds, Sta-Rite).