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Rainwater Harvesting Formula:
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Rainwater harvesting is the process of collecting and storing rainwater from rooftops or other surfaces for later use. It's an effective way to conserve water, reduce water bills, and provide an alternative water source for irrigation, toilet flushing, and other non-potable uses.
The calculator uses the rainwater harvesting formula:
Where:
Explanation: The formula calculates the maximum potential rainwater collection based on your roof area, local rainfall patterns, and the efficiency of your collection system.
Details: Properly sizing your rainwater tank is crucial for maximizing water collection, ensuring adequate supply during dry periods, and optimizing your investment. An undersized tank may overflow frequently, while an oversized tank may be unnecessarily expensive.
Tips: Measure your roof's catchment area accurately. Use historical rainfall data for your region. Typical runoff coefficients range from 0.6-0.9 for pitched roofs and 0.8-0.95 for metal roofs.
Q1: What is a runoff coefficient?
A: The runoff coefficient represents the efficiency of rainwater collection. It accounts for losses from evaporation, splashing, and first flush diversion.
Q2: How do I measure my roof area?
A: Calculate the footprint area of your roof (length × width). For pitched roofs, use the horizontal projection area, not the slanted surface area.
Q3: What rainfall data should I use?
A: Use average monthly or annual rainfall data for your location. Consider using the driest month's rainfall for conservative sizing.
Q4: Can I use rainwater for drinking?
A: With proper filtration and treatment, rainwater can be made potable. However, additional purification systems are required for drinking water.
Q5: How often should I maintain my rainwater system?
A: Regular maintenance includes cleaning gutters, inspecting filters, and checking tanks every 3-6 months for optimal performance.