Estimate your site's potential for water collection and determine the ideal storage capacity based on your roof size, local rainfall patterns, and consumption needs.
Total Annual Collection Potential:
0 Gallons
Recommended Tank Size:
3000 Gallons
Note: Your storage tank should ideally be sized to bridge the gap during your longest dry periods, but ensure it does not significantly exceed the annual collection potential of your site to avoid wasted capacity.
Sizing a tank requires balancing the harvest potential from your roof against your consumption during the longest expected drought.
Formula: Potential = Area (sq ft) × Rainfall (in) × 0.623 × Efficiency Factor
Example: A 2,000 sq ft metal roof in a region with 35 inches of annual rain and a 60-day dry spell.
It is the number of gallons collected by 1 inch of rain on 1 square foot of roof surface.
Not necessarily. A tank larger than your annual harvest potential will never fill, resulting in wasted investment.
Yes, metal is best for potable use; asphalt shingles may leach toxins and are better suited for irrigation.
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