Operator calculator
Wet Well Pumping Rate calculator
Find a pump's rate from how fast the wet well level drops.
Calculator
Pumping rate
119.68 gpm
- 1. 8 × 8 × 2.5 = 160 ft³
- 2. 160 ft³ × 7.48 = 1,196.8 gal
- 3. 1,196.8 gal ÷ 10 min = 119.68 gpm
For instructional use. Results assume the standard conversion factors shown on this page. Actual field calculations may need chemical strength, density, temperature, and other adjustments, so check your plant’s procedures.
Formula and inputs
pumping rate (gpm) = [length (ft) × width (ft) × drop (ft) × 7.48 gal/ft³] ÷ time (min)
| Input | Unit |
|---|---|
| Well length | ft |
| Well width | ft |
| Level drop | ft |
| Pumping time | min |
| Result: Pumping rate | gpm |
Conversion factors used: 7.48 gal per cubic foot.
When to use it
Lift station operators estimate a pump's actual output by timing how long it takes to lower the wet well a measured distance with no inflow.
Volume removed is length times width times the drop in feet, converted to gallons, then divided by the pumping time.
Applies to: Collection Systems, Wastewater Treatment.
Exam tip: Units are the whole problem: feet, then ft³, then gallons, then divide by minutes.
Study guides
Build the math skill behind the calculator
Water Operator Math Made Simple walks through the formulas step by step.
Water Operator Math Made Simple
A Step-by-Step Guide to the Math Every Water Operator Needs to Know