Sewage Pump Calculator
Calculate sewage ejector pump horsepower from flow rate, total dynamic head, and efficiency.
Results
Visualization
How It Works
Sewage ejector pumps lift waste from below-grade fixtures (basement bathrooms, laundry) up to the building sewer. Pump sizing depends on flow rate and total dynamic head (lift + friction losses).
The Formula
BHP = (GPM x TDH) / (3960 x Efficiency)
Variables
- BHP — Brake horsepower required
- GPM — Design flow rate
- TDH — Total dynamic head = static head + friction losses
- 3960 — Constant (conversion factor)
Worked Example
A basement bathroom with 30 GPM, 12 ft lift, 5 ft friction: BHP = (30 x 17) / (3960 x 0.50) = 0.26 HP. Use a 1/3 HP motor.
Practical Tips
- Always use a sewage-rated pump, not a sump pump
- Basin should be minimum 18" x 24" with sealed cover
- Check valve on discharge line is mandatory
- Grinder pumps are needed for long horizontal discharge runs