Calculate the recoverable fraction of rainwater harvesting after collection losses, treatment losses, and operating availability. The result separates captured volume from delivered reuse volume and reports the shortfall against an optional reuse demand. This helps identify whether losses, downtime, or source volume is limiting system output.
Overall recovery = collection efficiency × treatment recovery × system availability
Delivered volume equals source volume multiplied by overall recovery. Demand coverage is delivered volume divided by reuse demand.
The main result is the share of source water expected to reach end use after sequential efficiency and availability losses.
Efficiencies are multiplied because each stage acts on the volume remaining from the previous stage. Use measured stage data when available and avoid double-counting the same loss.
For 1,000 gal/day with 90% collection, 95% treatment recovery, and 98% availability, overall recovery is 0.90 × 0.95 × 0.98 = 83.79%, delivering 837.9 gal/day.
Each downstream stage receives only the water retained by the previous stage, so sequential efficiencies multiply.
No. Multiplying fractions from zero to one cannot produce a result greater than any individual stage efficiency.
Recovery and delivered volume are still calculated, but demand coverage is shown as not applicable.
Yes, if it is source water that does not enter the treatment and reuse path.
Keep physical treatment yield in treatment recovery and put operational outage time only in system availability.
| Input concept | Planning use |
|---|---|
| Volume or flow | Use the same gallon basis throughout the calculation. |
| Efficiency or allowance | Enter percentages as displayed, from 0 to 100. |
| Operating condition | Base it on the intended design period, not an unrelated annual peak. |