Wells & water/ CALCULATOR
Rainwater collection & overflow
Estimate one rainfall event and the amount a tank can receive.
Horizontal projected area that drains to the tank.
Choose a rainfall event, not an annual average.
Explicit assumption for losses before reaching storage.
Capacity excluding unusable dead storage.
Must not exceed usable capacity.
Potential collection
1,600 L
Added to storage
1,000 L
Surplus beyond free space
600 L
Single event, uniform collection factor and no withdrawals during rain. Does not size gutters or drainage, predict dry-period reliability, or establish water quality.