Find the right water storage tank capacity for your home — based on family size, supply frequency, and usage.
Handpicked products recommended for you — buy directly on Amazon India.
As an Amazon Associate we earn from qualifying purchases at no extra cost to you.
As per BIS IS 1172, per capita water requirement is 135 litres/day for residential areas with full facilities. A practical estimate for tank sizing is 150–200 litres per person per day.
A family of 4 needs about 600 litres/day (4 × 150 L). With daily supply, a 1,000 L tank is sufficient. If supply comes every 2 days, you need at least 1,500 litres.
Overhead tanks provide gravity-fed flow without a pump (energy efficient). Underground sumps store larger volumes. For multi-floor homes, both together is ideal — sump for large storage, overhead for daily gravity flow.
Polyethylene (plastic) tanks are most popular — lightweight, rust-free, and affordable. Triple-layer tanks prevent algae and UV damage. For underground sumps, RCC cement tanks are most durable.
Unlike countries with 24/7 pressurised municipal water supply, most Indian cities and towns receive water for only 2–6 hours a day — often at unpredictable times. During summer months or in drought-prone regions like Rajasthan, Maharashtra, and Tamil Nadu, supply may come only every other day or even less frequently. Proper water tank sizing is not a luxury but a necessity for uninterrupted daily life.
The Bureau of Indian Standards (BIS IS:1172) recommends 135 litres per person per day for urban residents. This includes drinking, cooking, bathing, laundry, and toilet flushing. However, actual usage varies significantly:
Overhead tanks (rooftop) provide water pressure through gravity. They need to be sized for daily consumption between municipal supply cycles — typically 1 to 1.5 days of usage. A family of 4 needs roughly 600–800 litres overhead capacity.
Underground sump tanks collect municipal supply and pump water up to the overhead tank. Sump capacity should cover 3–7 days of usage depending on supply reliability in your area — for a family of 4 in a city with erratic supply, a 3,000–5,000 litre sump is typical.