Another confusing task in building construction apart from the septic tank design is How to calculate the water tank size. But we can make it is easy to choose the right size of a water tank.

We had discussed the design of a septic tank for a house of 10 people in an earlier article.

Now, we are going to discuss how to calculate water tank capacity along with an example.

## How to Calculate Rectangular Rectangular Water Tank Size

To store the water for households internal and external usage. The water tank size is differ based on the number of the person in the house.

Mostly PVC tank installed for small-scale home. At the same time, the water tank has constructed by RCC or brick wall. The RCC or brick wall tank has plastered by waterproof admixture to avoid leakages.

You may aware to distribute the water for a village or town, the water was stored in the overhead tank from river or lake after chlorinated.

Ah! That was it topic we will discuss the Overhead tank design in the future post. Now we just discuss the water tank capacity calculation for a house.

## Water Tank Capacity Calculation

For an example, we are going to calculate the size of the water tank for a household 10 person.

Assume Number of people – 10 nos

#### Quantity of Water Usage

- Cooking – 5 Liters
- Bathing & Toilet – 85 Liters/Person
- Washing cloths & Utensils – 30 Liters
- Cleaning House – 10 Liters
- Other – 5 Litres

Total – **135 Litres/Day Approximately for a person**

**Hence for 10 Person = 135 x 10 = 1350 Litres – 1.35 cum**

Minimum depth of the Tank – 1m

Area of the Tank – 1.35/1 = 1.35 m

The Length and width ratio L: B – 2:1

2BxB = 1.35

B = 0.82 m

So the Length = 2 x 0.82 = 1.64m

Hence the Length = 1.64m

Width = 0.82m

Depth = 1m

The total capacity of the Tank = 1.34 Cum.

Add addtional 300mm for water free board.

You may interest to read Water-Cement Ratio of Concrete.

## Water Tank Size Calculator