Water tank size calculator
Find the water storage you need from the number of people and days of storage, using the BIS norm of 135 litres per person per day.
How it works
Litres = people × 135 × days of storage. We then suggest the nearest standard tank size.
- BIS recommends ~135 litres per person per day for domestic use.
- Keep 1–2 days of storage for supply gaps.
Water Tank Calculator FAQ
What size water tank for a family of 4?›
About 1,000 litres for one day, or 2,000 litres for two days of storage at 135 L/person/day.
Is 135 litres per person right?›
It's the BIS domestic norm; large gardens or extra bathrooms may need more.