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Rainwater Tank Size Formula:
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Rainwater tank sizing involves calculating the appropriate storage capacity needed to collect and store rainwater from your roof catchment area based on local rainfall patterns and usage requirements.
The calculator uses the rainwater tank sizing formula:
Where:
Explanation: The equation calculates the theoretical maximum rainwater collection potential based on rainfall volume and roof catchment area, adjusted for system efficiency losses.
Details: Correct tank sizing ensures adequate water supply during dry periods, prevents overflow during wet seasons, optimizes investment costs, and maximizes water conservation benefits.
Tips: Enter annual rainfall in millimeters, roof area in square meters, and efficiency factor (typically 0.85 for standard systems). All values must be positive numbers.
Q1: What is a typical efficiency factor for rainwater systems?
A: Most systems have an efficiency of 0.8-0.9, accounting for evaporation, first flush diversion, and system losses.
Q2: How do I find my local annual rainfall data?
A: Check the Bureau of Meteorology website or local council resources for rainfall data specific to your region.
Q3: Should I consider water usage patterns in tank sizing?
A: Yes, for optimal sizing, also consider your household water consumption patterns and the length of dry periods in your region.
Q4: What are common tank sizes available?
A: Common residential tank sizes range from 2,000 to 20,000 liters, with larger tanks available for commercial applications.
Q5: Are there rebates available for rainwater tanks in Australia?
A: Many local councils and state governments offer rebates and incentives for rainwater tank installation - check with your local authorities.