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Water Tank Size Equation:
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The water tank size calculation estimates the optimal tank capacity needed to capture rainwater from a catchment area based on local rainfall patterns. This is particularly important in Australia where water conservation is crucial.
The calculator uses the water tank size equation:
Where:
Explanation: The equation calculates the theoretical maximum water capture and applies a 90% efficiency factor to account for evaporation, first flush diversion, and other system losses.
Details: Properly sizing a water tank ensures optimal water capture during rainfall events while avoiding overspending on unnecessarily large tanks. Correct sizing helps maximize water self-sufficiency and supports sustainable water management practices.
Tips: Enter catchment area in square meters and average rainfall in millimeters. Use local rainfall data for accurate results. All values must be valid (area > 0, rainfall > 0).
Q1: Why is there a 0.9 efficiency factor?
A: The 0.9 factor accounts for system losses including evaporation, first flush diversion, splash loss, and incomplete drainage from the catchment surface.
Q2: What's a typical catchment area for residential properties?
A: Residential roof areas in Australia typically range from 100-300 m², depending on house size and design.
Q3: How do I find accurate rainfall data for my area?
A: The Bureau of Meteorology provides detailed rainfall data for locations across Australia, including average monthly and annual rainfall figures.
Q4: Should I consider seasonal rainfall variations?
A: Yes, for optimal tank sizing, consider the dry season length and average rainfall during the wettest months to ensure adequate supply year-round.
Q5: Are there government regulations for tank sizing?
A: Some Australian local councils have specific requirements or guidelines for rainwater tank sizing, particularly for new developments.