Learn water tank size calculation using formula, examples, and free Excel sheet. Calculate tank capacity for residential and commercial buildings easily.
1. ✅ Quick Answer
👉 Water tank size is calculated using:
👉 Tank Capacity (Liters) = Number of People × Daily Water Demand (LPCD) × Storage Days
✔ Standard value (India): 135 LPCD (liters per person per day)
👉 Example:
5 people → 5 × 135 = 675 Liters
| Tank Capacity | Approx Size (Feet) | Usage |
|---|---|---|
| 200 litre water tank size | 2 × 1 × 1 | Small use |
| 500 litre water tank size | 3 × 2 × 2 | 1–2 persons |
| 1000 litre water tank size | 4 × 3 × 2 | Small house |
| 2000 litre water tank size | 6 × 4 × 3 | Medium house |
| 10000 litre water tank size | 10 × 8 × 6 | Apartments |
2. 📊 Water Tank Size Chart
| Building Type | Water Demand (LPCD) |
|---|---|
| Residential | 135 |
| Hostel | 90 |
| Office | 45 |
| School | 30 |
👉 These values are based on standard Indian plumbing practices.
3. 🧠 What is Water Tank Size Calculation?
Water tank size calculation is the process of determining how much water storage is required for a building to ensure continuous supply and proper system operation.
It is important for:
- Residential buildings
- Apartments
- Commercial buildings
- Industrial facilities
👉 Proper tank sizing ensures:
- No water shortage
- Stable pressure
- Efficient plumbing system
4. 📐 Formula
👉 Tank Capacity (Liters) = Population × LPCD × Storage Days
Where:
- Population = Number of users
- LPCD = Liters per person per day
- Storage Days = Backup duration (usually 1 day)
📦 Tank Volume Formulas
👉 Rectangular tank:
👉 Volume = Length × Width × Height
👉 Circular tank:
👉 Volume = π × r² × h
5. 🧮 Step-by-Step Calculation
Step 1: Determine population
Example: 6 persons
Step 2: Select LPCD
Residential = 135 LPCD
Step 3: Choose storage days
Typically = 1 day
Step 4: Calculate total requirement
👉 6 × 135 × 1 = 810 Liters
Step 5: Select tank size
👉 Choose next standard size → 1000 Liters
6. 📊 Example (Real Case)
🏢 Apartment Example
- 10 flats
- 5 persons per flat
👉 Total population = 50
👉 Tank size:
👉 50 × 135 = 6750 Liters
✔ Recommended tank: 7000–8000 Liters
🏬 Commercial Building Example
- 20 people
- LPCD = 45
👉 20 × 45 = 900 Liters
✔ Tank size: 1000 Liters
7.🏗️ Drawing / Diagram
👉 A typical water tank system includes:
- Inlet pipe
- Outlet pipe
- Overflow pipe
- Drain pipe
- Vent pipe
👉 Proper pipe arrangement ensures efficient operation.
8. 📥 Download Water Tank Calculation Excel
👉 Download Water Tank Size Calculation Excel Sheet
Includes:
✔ Automatic population input
✔ LPCD selection
✔ Tank capacity calculation
✔ Ready-to-use formulas
👉 Useful for engineers, students, and site designers.
9. ❓ FAQ
What is standard water demand per person?
👉 135 liters per day (India standard)
What is minimum water tank size for a house?
👉 500–1000 liters depending on usage
How to calculate overhead tank size?
👉 Based on daily water demand and storage requirement
What is difference between overhead and underground tank?
- Overhead tank → Provides pressure
- Underground tank → Stores bulk water
How many days storage is required?
👉 Usually 1 day (can increase for backup)
What is the size of 1000 litre water tank?
👉 Approx: 4 ft × 3 ft × 2 ft
What is the size of 2000 litre water tank?
👉 Approx: 6 ft × 4 ft × 3 ft
What is the size of 10000 litre water tank?
👉 Approx: 10 ft × 8 ft × 6 ft
What size water tank do I need?
👉 Depends on:
- Number of people
- Daily water use
👉 Use tank calculation formula.
What is standard water tank size?
👉 Common sizes:
- 500 L
- 1000 L
- 2000 L
- 5000 L
What is Sintex loft water tank size chart?
👉 Common Sintex tank sizes:
- 500 L
- 750 L
- 1000 L
- 2000 L
👉 Widely used in Indian homes.
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