How does the rainwater harvesting calculator work?
Catchment water yield, distinct from instantaneous roof drainage design flow and tank geometry. Use rainfall for the same period as demand. Annual total rainfall cannot predict whether a tank stays full through a dry season.
Which measurements do you need for rainwater harvesting?
Use rainfall for the same period as demand. Annual total rainfall cannot predict whether a tank stays full through a dry season. Measure the actual installed geometry or quoted quantity rather than substituting a nominal product size.
Which formula calculates rainwater harvesting?
Collected liters = catchment m² × rainfall mm × runoff coefficient − stated losses; stored volume = min(collected, available capacity).
What does a rainwater harvesting worked example show?
A 100 m² roof receiving 20 mm rainfall with runoff coefficient 0.8 yields 1,600 liters before first-flush loss.
Which units apply to rainwater harvesting?
Use the labeled units in the input reference below. The Imperial / Metric selection converts fields with dynamic unit labels. Fixed-unit fields retain the units printed in their labels.
Leave optional inputs blank when unavailable. Required fields and paired data are checked before a result is displayed.
| Input | Units | When used |
|---|---|---|
| Effective catchment area (m²) | as labeled | all modes |
| Rainfall for chosen period (mm) | as labeled | all modes |
| Verified runoff coefficient (0 to 1) | as labeled | all modes |
| First-flush and other collection loss (liters) | as labeled | all modes |
| Available storage capacity (liters) | as labeled | all modes |
| Demand during selected period (liters) | as labeled | all modes |
Which assumptions change the rainwater harvesting result?
Catchment water yield, distinct from instantaneous roof drainage design flow and tank geometry. Use rainfall for the same period as demand. Annual total rainfall cannot predict whether a tank stays full through a dry season.
How should you check the rainwater harvesting estimate?
Use rainfall for the same period as demand. Annual total rainfall cannot predict whether a tank stays full through a dry season. Keep measured values separate from any extra allowance or quoted price. Check the resulting unit and rounding before ordering or using the result.
How can you compare rainwater harvesting scenarios?
Calculate one baseline and add it to comparison. Change one measured input or verified product value and calculate again. Comparison keeps the itemized inputs and results so the changed assumption remains visible.
How can you save or share the rainwater harvesting result?
After calculation, copy or share the result, download the worksheet or print the inputs and result. Embed and citation controls are in the header. Clear changes removes the current worksheet, and a browser refresh opens blank numeric inputs.
Which related tools help with rainwater harvesting?
Use Pool Volume Calculator, Tank Volume Calculator, Pool Salt Calculator for related project quantities. Each tool has its own scope; avoid transferring a result without checking its unit and assumptions.
