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Measured flow → daily runtime → pressure-tank cycle → storage buffer

Well Pump Runtime, Cycling & Storage Calculator

Convert a measured flow test into daily runtime and energy, examine pressure-tank cycling from entered drawdown, and calculate storage autonomy or refill time when well production and household demand differ.

Measure actual flowUse gallons collected and elapsed time instead of a nameplate-only estimate.
Daily runtimeTranslate demand into pump minutes, entered energy and production margin.
Pressure-tank cyclingUse actual drawdown at the entered pressure settings, not nominal tank size.
Storage bufferCalculate days to reserve, outage storage and net refill time.
Planning example: 400 gallons/day supplied by a 10 gpm pump requires about 40 minutes of pump runtime. At 1.5 kW, that is about 1 kWh before accounting for real motor, pressure and control conditions.

Calculate measured pump or source flow

Time a known container or meter volume under a stable test condition. A short flow test does not establish long-term well recovery or water quality.

Measured flow

Gallons/minute—
Gallons/hour—
Time per 100 gallons—
Time per 1,000 gallons—
Repeat tests under representative conditions and compare with the pump curve, well contractor data and measured water levels where applicable.

Copy or print the current well-system plan

Use a mode above to generate a planning summary.

Separate pump flow from sustainable well production

A pump can move water faster than a well replenishes. The daily-runtime mode therefore keeps measured delivery flow separate from sustainable gallons per day. Use a qualified well test, water-level records or contractor data for production planning.

daily pump runtime = daily gallons ÷ measured pump gallons per minute

Storage can bridge short-term differences between peak household demand and source production, but it does not create water or prove that the well can sustain a schedule.

Pressure tank drawdown matters

The usable drawdown between pressure-switch cut-out and cut-in is smaller than nominal pressure-tank volume. Use the manufacturer's drawdown table for the actual pressure settings or a measured value.

The cycling model estimates run and off time only for the entered steady demand. If active demand meets or exceeds pump flow, the model reports continuous operation rather than a repeated tank cycle.