Wastewater/ CALCULATOR
Sump pit storage and pump cycling
Estimate active pit volume, fill time, drain time and starts per hour from measured levels and flows.
Measure the clear internal diameter.
Use the observed vertical travel between control levels.
Estimate during a representative wet condition.
Use measured discharge flow at the real head, not a free-flow maximum.
Active storage between levels
56.55 L
Net drawdown flow while pumping
68.00 L/min
Time from pump-off to pump-on
4.71 min
Pump run time per cycle
0.83 min
Estimated starts per hour
10.82 starts/h
Pump-flow margin above inflow
566.67 %
Interpretation:The pump lowers the level at 68 L/min and this scenario produces about 10.82 starts per hour. Confirm the permitted cycling with the pump manufacturer.
A cylindrical pit, steady inflow, unchanged pump performance and simple on/off control. Verify the manufacturer’s minimum run time and starts-per-hour limit. Debris, check-valve leakage, rising head and power loss are separate risks.