sq ft
in
Please enter valid area and rainfall values.
Total Runoff Volume
—
—
Harvestable Water
—
—
Runoff Coefficient
—
Lost to Absorption
—
Overflow Risk
—
Recommended Storage Tank Sizes
💧 Harvesting Tips
🌊 Overflow Management
Measure Rainfall at Your Property
Ambient Weather WS-2902C Osprey
Get accurate local rainfall data from your own rain gauge so you can calculate runoff with real numbers, not regional estimates.
Uses the Rational Method: Q = C x i x A. Runoff coefficient (C) values based on standard civil engineering references. Harvestable volume applies a 90% collection efficiency factor for first-flush losses and system inefficiency. Not a substitute for professional drainage assessment.