Rainwater at the House: First-Flush Sizing, the Dry-Spell Tank, and Regrowth in the Tank That Stores It

SIMULATED, NOT MEASURED. For a 60 m2 roof and 1091 mm of rain, yield is 55641 L/year, a 1.0 mm first-flush diverter discards 60 L/event (7% of yield), a 45-day dry spell needs 1125 L of storage, and tank regrowth is fast enough that rainwater must be treated at draw. Hardware is US$2.329 per 1000 L before treatment. Nothing was built or field-tested.