# WATER DEMAND AND WATER TANK SIZE & VOLUME CALCULATION

### Domestic Water Demand

- The total domestic water consumption usually amounts to 50 to 60% of the total water consumption.
- The I.S. Code lays down a limit of water consumption between 135 to 225 litres per capita per day (/pcd).
- Under ordinary conditions (as per I.S. code) the minimum domestic water demand for a town or a city with a full flushing system Should be taken at 200 lpcd. Although it can be reduced to
**135****lpcd**for economically weaker sections and LIG colonies depending upon prevailing conditions.

**1. Minimum domestic water consumption (Annual average) for Indian towns and cities with Full Flushing systems as per 1172-1993.**

**2. Minimum domestic water consumption (Annual average) for weaker sections and LIG (Lower Income Group) Colonies in small Indian Towns and Cities.**

#### WATER TANK CAPACITY CALCULATION

For a Small LIG (Lower Income Group) family = 5 Members

Water Consumption in 1 Day = 135 litre

For 5 member in a Day = 135 x 5

For 5 members in a Day = 675 lit.

Assume the water consumption of 1000 lit.

We know water density is 1000 lit/m3

1m3 = 1000 lit.

Water tank volume is = 1m3

**WATER TANK SIZE CALCULATION**

Water tank volume is = 1m3

Volume of water tank is DxBxL

Assume water tank depth as your required = 0.5m

Depth is water tank is, ** D= 0.5 m**

Area of water tank = 1/0.5 = 2

Area of water tank, L x B = 2 meter squre

Suppose L= 2B

2B X B = 2

B^2 = 2/2

B^2 =1

B = √1

B = 1

Width of water tank is,** B= 1 m**

Put value of B in assume equation, ** Suppose L= 2B**

L = 2X1

L = 2

Length of water tank is,** L = 2 m**

Overall water tank site is DxBxL

**0.5x1x2 = 1 meter cube**

Here is a plan of the water tank and cross-section of the water tank

Excel Sheet For Size Calculation –