Water Tank Calculation — Sizing for Any Household

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Overview

Correctly sizing a water storage tank prevents running out during supply interruptions while avoiding the cost of an oversized tank.

Daily requirement = People × 150 litres | Storage = Daily × Storage days desired

Standard formula used by professionals worldwide

Family of 5 × 150L × 3 days = 2,250L → buy 2,500L tank with 10% safety margin

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Units: Always use consistent units throughout
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150-200 litres for a typical household including all uses.

Tank volume ÷ Fill rate (litres per minute from your supply). Account for simultaneous usage.

Food-grade polyethylene (plastic) is most common. Stainless steel for premium. Concrete for large underground tanks.

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