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Septic Tank Sizing Formula:
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The New Zealand septic tank sizing formula calculates the appropriate tank capacity based on the number of persons using the system. The standard formula is C = 150 × P × 2, where C is the tank capacity in liters and P is the number of persons.
The calculator uses the NZ septic tank sizing formula:
Where:
Explanation: This formula provides a standard calculation for determining the minimum septic tank capacity required for a given number of occupants in New Zealand.
Details: Correct septic tank sizing is crucial for efficient wastewater treatment, preventing system overload, and ensuring compliance with New Zealand regulations. An appropriately sized tank allows for proper settling and treatment of solids.
Tips: Enter the number of persons who will be using the septic system. The calculator will determine the recommended minimum tank capacity in liters according to New Zealand standards.
Q1: Why is the formula multiplied by 2?
A: The multiplication by 2 provides a safety factor to account for peak usage times and ensures the system can handle temporary increases in wastewater flow.
Q2: Are there different requirements for commercial properties?
A: Yes, commercial properties often require specialized sizing calculations based on the specific type of business and expected wastewater volume.
Q3: What other factors should be considered besides number of persons?
A: Soil type, percolation rate, property slope, and local council regulations may also affect septic system design and requirements.
Q4: How often should a septic tank be pumped?
A: Typically every 3-5 years, but this can vary based on tank size, usage, and the number of occupants.
Q5: Is council approval required for septic systems in NZ?
A: Yes, all septic systems require resource consent and building consent from your local council before installation.