The size of a water tank for a family depends on various factors such as daily water usage, the number of people, and local water availability. A general guideline is to estimate about 50-75 gallons per person per day. Here’s a basic calculation:

1. For a family of 2: 100-150 gallons per day.

2. For a family of 3: 150-225 gallons per day.

3. For a family of 4: 200-300 gallons per day.

4. For a family of 5: 250-375 gallons per day.

5. For a family of 6: 300-450 gallons per day.

Now first try to understand estimation of water requirement based on Number of persons and per capita demand, it not depend on how size is home. Do you think a huge quantity of water used for flush of toilets, taking showers and baths, washing your cloths and utensil, cocking food, drinking and others domestic purpose.

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Per capita demand is volume of Water in litres used by one person in one day, that’s help in deciding the water tank size and water consumption per day by your family members in your residential house those have 2, 3 and 4 bedroom and for 2, 3, 4, 5 and 6 people.

In two bedroom house, there is parents father and mother, they have suppose two kids, so number of people in two bedroom house is about 4, then what should we water tank size for 2 bedroom house.

In 3 bedroom house, there is a parents grandfather, grandmother, father and mother, they have supposed two kids so number of people in three bedroom house is about 6, then what should be water tank size for 3 bedroom house.

In 4 bedroom house, there is a parents grandfather, grandmother, uncle, Aunty, father and mother, they have supposed four kids, so number of people in 4 bedroom house is about 10, then what should be water tank size for 4 bedroom house.

In this topic we explain how to calculate water tank size for family of 2, 3, 4, 5 and 6, calculation of water tank size and water tank size for 2, 3 and 4 bedroom house.

**How to calculate water tank size for family of 2, 3, 4, 5 and 6**

Estimation of water quantity based on Number of persons and per capita demand, it not depend on how size is home. Per capita demand is volume of Water in litres used by one person in one day, that’s help in deciding the water tank size and water consumption per day.

Water requirement (Volume) = No. of persons × per capita demand

First of all we need to be sure of per capita demand. Actually it varies based on location and income. According to Indian standard water per capita demand is approx 135litres per person per day for lower income group and approx 180litres to 200litres per person per day for medium and higher income group.

In india, For example it is approximately 250 litre/person/day for Bombay, 300 litres/person/day for Delhi, 226 litres/person/day for Kolkata and 115 litres/person/day for Chennai. Considering the building is residential, we shall take 200 l/p/d for domestic uses (city/town) purpose. Now the we will get water requirement by multiplying estimated no. of persons in the building.

Suppose we have 4 family members in a house and we shall take approx 200l/p/d for domestic uses, then estimation of water requirement, water requirement (Volume) = No. of persons × per capita demand, 4×200= 800litres per day.

**Calculation of water tank size/ determination of water tank size**

then estimation of water requirement, water requirement (Volume) = No. of persons × per capita demand, 4×200= 800litres per day. This will help you calculation of water tank size and how to determine water tank size.

For a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of four would be needing 800 litres of water per day. Be care depth preferably do not go beyond 7–8 ft.

Volume = Depth x Area

Area = a x a (Square) or Length x Breadth (Rectangular),

Capacity of water is 800litres = 0.8m3, taking one dimension depth is equal to 1.8m and their side is 0.67m for square water tank, then size of water tank for 4 family members is 1.8m × 0.67m × 0.67m of 800litres capacity.

**Water tank size for family of 2**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of two, a water tank with a capacity of between 100 and 150 gallons is usually sufficient to cover the family’s basic needs.

We have given number of person is 2 and water consumption per capita is 200litres, so total volume of waters = 2×200ltrs = 400 litres, so we need 400 litres capacity of water tank for 2 family members.

Capacity of water tank is 400litres = 0.4m3, taking one dimension depth is equal to 1.2m and their side is 0.58m for square water tank, then size of water tank for 2 family members is 1.2m × 0.58m × 0.58m of 400litres capacity.

Water tank size for family of 2:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 2 members would be needing 400 litres of water per day and their minimum size of water tank is 1.2m × 0.58m × 0.58m in respects of its depth, Length and width of 400litres capacity.

**Water tank size for family of 3**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of three, a water tank with a capacity of between 150 and 225 gallons is usually sufficient to cover the family’s basic needs.

We have given number of person is 3 and water consumption per capita is 200litres, so total volume of waters = 3×200ltrs = 600 litres, so we need 600litres capacity of water tank for 3 family members.

Capacity of water tank is 600litres = 0.6m3, taking one dimension depth is equal to 1.5m and their side is 0.63m for square water tank, then size of water tank for 3 family members is 1.5m × 0.63m × 0.63m of 600litres capacity.

Water tank size for family of 3:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 3 members would be needing 600 litres of water per day and their minimum size of water tank is 1.5m × 0.63m × 0.63m in respects of its depth, Length and width of 600litres capacity.

**Water tank size for family of 4**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of four, a water tank with a capacity of between 200 and 300 gallons is usually sufficient to cover the family’s basic needs.

Water tank size for family of 4:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 4 members would be needing 800 litres of water per day and their minimum size of water tank should be 1.8m × 0.67m × 0.67m in respects of its depth, Length and width of 800litres capacity.

**Water tank size for family of 5**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of five, a water tank with a capacity of between 250 and 375 gallons is usually sufficient to cover the family’s basic needs.

Water tank size for family of 5:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 5 members would be needing 1000 litres of water per day and their minimum size of water tank should be 1.8m × 0.75m × 0.75m in respects of its depth, Length and width of 1000litres capacity.

**Water tank size for family of 6**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of six, a water tank with a capacity of between 300 and 450 gallons is usually sufficient to cover the family’s basic needs.

Water tank size for family of 6:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 6 members would be needing 1200 litres of water per day and their minimum size of water tank should be 1.8m × 0.82m × 0.82m in respects of its depth, Length and width of 1200litres capacity.

**Water tank size for family of 7**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of seven, a water tank with a capacity of between 350 and 525 gallons is usually sufficient to cover the family’s basic needs.

Water tank size for family of 7:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 7 members would be needing 1400 litres of water per day and their minimum size of water tank should be 1.8m × 0.88m × 0.88m in respects of its depth, Length and width of 1400litres capacity.

**Water tank size for family of 8**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of eight, a water tank with a capacity of between 400 and 600 gallons is usually sufficient to cover the family’s basic needs.

Water tank size for family of 8:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 8 members would be needing 1600 litres of water per day and their minimum size of water tank should be 1.8m × 0.94m × 0.94m in respects of its depth, Length and width of 1600litres capacity.

**Water tank size for family of 9**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of nine, a water tank with a capacity of between 450 and 675 gallons is usually sufficient to cover the family’s basic needs.

Water tank size for family of 9:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 9 members would be needing 1800 litres of water per day and their minimum size of water tank should be 1.8m × 1m × 1m in respects of its depth, Length and width of 1800litres capacity.

**Water tank size for family of 10**

As a general guide, approximately 50-75 gallons per person per day is estimated. For a family of ten, a water tank with a capacity of between 500 and 750 gallons is usually sufficient to cover the family’s basic needs.

Water tank size for family of 10:- for a standard normal house, an estimated 200 litres per person is the thumb rule. so for a family of 10 members would be needing 2000 litres of water per day and their minimum size of water tank should be 2m × 1m × 1m in respects of its depth, Length and width of 2000litres capacity.

**Water tank size for 2 bedroom house**

The recommended size for a water tank in a 2-bedroom house depends on factors like water usage, local climate, and availability of other water sources. On average, a tank with a capacity of 200 to 300 gallons is often suitable for residential use.

Water tank size for 2 bedroom house:- for a standard normal 2 bedroom house, an estimated 200 litres per person is the thumb rule. so for a family of 4 members who living in 2 bedroom house would be needing 800 litres of water per day and their minimum size of water tank should be 1.8m × 0.67m × 0.67m in respects of its depth, Length and width of 800litres capacity.

**Water tank size for 3 bedroom house**

The recommended size for a water tank in a 3-bedroom house depends on factors like water usage, local climate, and availability of other water sources. On average, a tank with a capacity of 300 to 450 gallons is often suitable for residential use.

Water tank size for 3 bedroom house:- for a standard normal 3 bedroom house, an estimated 200 litres per person is the thumb rule. so for a family of 6 members who living in 3 bedroom house would be needing 1200 litres of water per day and their minimum size of water tank should be 1.8m × 0.82m × 0.82m in respects of its depth, Length and width of 1200litres capacity.

**Water tank size for 4 bedroom house**

The recommended size for a water tank in a 4-bedroom house depends on factors like water usage, local climate, and availability of other water sources. On average, a tank with a capacity of 500 to 750 gallons is often suitable for residential use.

Water tank size for 4 bedroom house:- for a standard normal 4 bedroom house, an estimated 200 litres per person is the thumb rule. so for a family of 10 members who living in 4 bedroom house would be needing 2000 litres of water per day and their minimum size of water tank should be 2m × 1m × 1m in respects of its depth, Length and width of 2000litres capacity.

**Conclusions:-**

The recommended water tank size for a family depends on factors like daily water usage and local climate. On average, a family of 2 might need around 150 gallons, a family of 3 around 225 gallons, a family of 4 around 300 gallons, a family of 5 around 375 gallons, and a family of 6 around 450 gallons.