Underground Rainwater Storage Sizing Estimator

Estimate module count and net storage from catchment area and rainfall — a starting point for your quote, not a final engineering figure.

Catchment Area (roof + paved surface, m²)

Design Storm Rainfall (mm, single event)

Runoff Coefficient

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Runoff Volume (m³)

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Modules Needed (95% void)

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40HQ Containers

Based on 1000×500×500mm modules at 95% void ratio (237.5L net storage each) and 330 m³ per 40HQ container. Design-storm intensity, not annual rainfall, should drive your final sizing — confirm against local hydrology data before finalizing an order.

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