Home
Back
Roof Rain Collection Formula:
| From: | To: |
Roof rain collection is a method of harvesting rainwater by collecting runoff from roof surfaces. This sustainable practice helps conserve water resources and can provide water for various non-potable uses such as irrigation, toilet flushing, and laundry.
The calculator uses the roof rain collection formula:
Where:
Explanation: The formula calculates the volume of rainwater that can be collected from a roof surface based on the area and rainfall amount.
Details: Rainwater harvesting reduces demand on municipal water supplies, lowers water bills, helps prevent stormwater runoff, and provides a sustainable water source for landscaping and other non-potable uses.
Tips: Enter roof area in square feet and rainfall in inches. Both values must be positive numbers. The calculator will provide the estimated rainwater collection in gallons.
Q1: What is the 0.623 conversion factor?
A: This factor converts square feet and inches to gallons (1 cubic foot = 7.48 gallons, and 1 inch of rain on 1 square foot = 0.0833 cubic feet).
Q2: How accurate is this calculation?
A: The calculation provides a theoretical maximum. Actual collection may be less due to evaporation, splash loss, and collection system efficiency (typically 80-90% of theoretical maximum).
Q3: What types of roofs are best for rainwater collection?
A: Metal, tile, and slate roofs are most efficient. Asphalt shingles work well but may leach some chemicals. Green roofs have lower collection efficiency.
Q4: How much rainfall should I expect to collect annually?
A: Multiply your roof area by annual rainfall (in inches) by 0.623. For monthly estimates, use monthly rainfall data.
Q5: What can collected rainwater be used for?
A: Irrigation, toilet flushing, laundry, car washing, and other non-potable uses. With proper treatment, it can be used for drinking water.