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Rainwater Tank Size Equation:
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The rainwater tank size calculation helps determine the appropriate tank capacity needed to collect and store rainwater from your roof area based on local rainfall patterns and collection efficiency. This is particularly important in Australia where water conservation is crucial.
The calculator uses the rainwater tank size equation:
Where:
Explanation: The equation calculates the volume of rainwater that can be collected from your roof area during rainfall events, accounting for system efficiency losses.
Details: Rainwater harvesting is essential in Australia due to variable rainfall patterns and frequent drought conditions. Proper tank sizing ensures optimal water storage for household use, garden irrigation, and emergency water supply.
Tips: Enter roof area in square meters, average rainfall in millimeters, and collection efficiency (typically 0.85 for standard systems). All values must be positive numbers.
Q1: What is a typical collection efficiency value?
A: Most well-designed rainwater collection systems have an efficiency of 80-90% (0.8-0.9), accounting for first flush diversion, evaporation, and minor losses.
Q2: How do I measure my roof area?
A: Calculate the footprint area of your roof (length × width) and multiply by the roof pitch factor if needed. For complex roofs, consult a professional.
Q3: What rainfall data should I use?
A: Use average annual rainfall data for your specific location from the Bureau of Meteorology for long-term planning, or seasonal data for specific usage needs.
Q4: Are there regulations for rainwater tanks in Australia?
A: Yes, local council regulations may specify minimum/maximum tank sizes, installation requirements, and connection to household plumbing. Always check local guidelines.
Q5: How often should I maintain my rainwater tank?
A: Regular maintenance including gutter cleaning, first flush device checking, and tank inspection should be done every 6-12 months to maintain efficiency.