Rainwater Harvesting Tank Sizer

Sizes a rainwater tank two ways at once: by what the roof and the local rainfall can actually collect, and by the minimum the Green Building Code asks for where it applies.

• The yearly and monthly yield from your roof and rainfall.
• Storage needed for the demand and the dry days you want to cover.
• The first-flush volume to divert.
• The Green Building Code minimum, shown beside the yield-based size.
• Follows: Philippine Green Building Code, rainwater harvesting.
• Use rainfall records for the actual site. A tank sized on the yearly average alone can run dry through a long dry season.

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• Step-by-step guide: Rainwater Harvesting Tank Sizer