Overhead Tank (OHT) Capacity Calculation: Complete Guide by Relgrow

Overhead Tank (OHT) Capacity Calculation: Complete Guide by Relgrow

Introduction
Water supply is a vital part of any home or commercial building. The overhead tank (OHT) ensures a steady water flow through taps, showers, and other fixtures by using gravity. Choosing the right tank size is crucial—too small leads to shortages, too large wastes money and space. At Relgrow, we simplify OHT capacity calculation, helping you select the ideal tank for your needs, ensuring efficiency, hygiene, and cost savings.

What is an Overhead Tank (OHT)?

An OHT is a water storage tank placed at height, usually on rooftops. Storing water at elevation creates natural pressure, allowing water to flow to multiple points without pumps. The right tank size ensures:

• Constant water availability
• Reduced construction and electricity costs
• Hygienic storage without water stagnation
• Proper load management on rooftops

Why Proper OHT Capacity Calculation Matters

Selecting the correct OHT size prevents common issues:

• Running out of water during peak hours
• Overspending on unnecessarily large tanks
• Stagnant water and hygiene concerns
• Excessive rooftop load affecting structure

Factors to Consider Before Calculating OHT Capacity

1️⃣ Number of People in the House – More people = higher water requirement
2️⃣ Daily Water Usage per Person – Avg. 135–150 liters in India
3️⃣ Purpose of Usage – Domestic vs. gardening or car washing
4️⃣ Number of Bathrooms & Taps – More outlets need higher capacity
5️⃣ Storage Days – Water backup duration (1–2 days)
6️⃣ Roof Load Capacity – Ensure structure can safely bear full tank weight

Basic OHT Capacity Formula

Total OHT Capacity (liters)=Number of People×Daily Water Usage per Person×Number of Storage Days\text{Total OHT Capacity (liters)} = \text{Number of People} \times \text{Daily Water Usage per Person} \times \text{Number of Storage Days}Total OHT Capacity (liters)=Number of People×Daily Water Usage per Person×Number of Storage Days

Example:

• Family members: 5
• Daily usage/person: 135 liters
• Storage days: 1

Calculation: 5 × 135 × 1 = 675 liters → Round off to standard 750 liters tank

For 2-day backup: 5 × 135 × 2 = 1,350 liters → 1,500 liters tank

Standard OHT Sizes in India

• 500 liters
• 750 liters
• 1000 liters
• 1500 liters
• 2000 liters
• 5000 liters (for larger buildings)

Types of Overhead Water Tanks

1. Plastic (PVC) – Lightweight, affordable, easy to install
2. Concrete – Heavy-duty, long-lasting, ideal for large buildings
3. Stainless Steel – Hygienic, rust-proof, premium option
4. FRP (Fiber Reinforced Plastic) – Corrosion-resistant, durable

Expert Tips for Choosing the Right Tank

✅ Select food-grade or rust-proof materials
✅ Check ISI mark or reputed brand quality
✅ Ensure tightly fitting lid to prevent contamination
✅ Confirm rooftop can handle full tank weight
✅ Provide overflow and vent system for safety

FAQs

Q1: Can multiple small tanks replace a large OHT?
A1: Yes, especially for apartments or multi-unit buildings.

Q2: How often should I clean my OHT?
A2: At least once every six months.

Q3: How do I know if my current OHT is sufficient?
A3: Track usage and refill frequency; frequent shortages indicate the need for a larger tank.

Q4: Plastic vs. concrete OHT – which is better?
A4: Plastic is ideal for homes due to ease of installation; concrete suits large structures.

Conclusion

Proper calculation of OHT capacity is essential for uninterrupted water supply, cost savings, and hygiene. Mismatched tank sizes can lead to water shortages or unnecessary expenses. With Relgrow’s simple method, you can confidently choose the right size and type of tank for your home or building, ensuring safety, efficiency, and long-term reliability.

📞 Contact Relgrow for personalized advice, tank selection, and installation guidance.

Quick Links

Interior Designers In Electronic City
Interior Designers In HSR Layout
Interior Designers In Bellandur
Interior Designers In Koramangala
Interior Designers In Indiranagar
Interior Designers In Whitefield
Interior Designers In Jayanagar
Interior Designers In Yelahanka
Interior Designers In JP Nagar
Interior Designers In Marathahalli
Interior Designers In Bannerghatta Road
Interior Designers In Hebbal
Interior Designers In BTM Layout
Interior Designers In Banaswadi
Interior Designers In Kanakapura Road
Interior Designers In Varthur
Interior Designers In KR Puram
Interior Designers In Sahakara Nagar
Interior Designers In Banashankari
Interior Designers In Rajajinagar