Rain Water Harvesting- builtify

Water is everywhere in the world. But the amount of sweet water or usable water is very less . we can say it is the most scarce resource in the world right now. Many research organizations are saying that water will be finished in future. So to save water for our future generations we need to take step to save this resource.

Photo courtesy:Neerain

This can be done in various ways like not wasting water while using in your home. Using required amount of water during car wash or other home washing works. This is the consumption part saving   But if we can save the source part then that will have a great impact on our environment.

So this concept is rain water harvesting. It has been used by many people as it has lot of benefits. In india we have rainy season and it is a better option to use that resource of water. But many people in India don’t go for rainwater harvesting because they think it is an investment which won’t give any profit. But it is a way to making your building green building rather than expense.

Rain water can supplement some of your water needs, if harnessed properly. Harvested rainwater can serve a variety of purposes, some of which include:

Increases ground water recharge

Photo courtesy:Istock

Reduces sea water ingress in coastal areas

Provide water for general purposes

Photo courtesy:Pinterest

There is a tremendous potential for water harvesting in our country . Consider your own building with a flat terrace area of square meters. Assume that the average rainfall in your area is 40” or 1000mm approximately . Thus , even if only 60 percent of total rainfall is harvested , you will be able to harvest 100 x 1.0 x 0.6 = 60 cum i.e. 60,000 litres of water a year.

This volume is more than a year ‘s (about 400 days) domestic water requirement of 1 person , assuming average daily water requirement for domestic use per person is 150 litres.

If we use the stored rainwater only during the monsoons for washing clothes , washing cars etc., you will help in reducing the overall water needed from public utilities and therefore prevent water shortage in the summer.

In some developed countries, buildings are required to supplement their water needs through rainwater harvesting.

What is rain water harvesting ?

Rain water harvesting (RWH) is a technique of collection and storage of rainwater into natural reservoirs or tanks.

How it works ?

The rain water from a large surface is collected I.e from roofs and then collected into underground or overground tanks.

Methods of rain water harvesting :-

There are two types of rain water harvesting.

  1. I) Rooftop rain water harvesting
  2. II) Surface runoff water harvesting

Surface runoff water harvesting:-

In urban area rain water flows away as surface run off. This surface could be caught up and cane be recharged aquifers.

Rooftop rain water harvesting method:-

In Rooftop rain water harvesting is the technique in which roof water is collected from roofs and then stored in tanks and reservoirs.

It can be applied mostly in urban areas.

Process of rain water harvesting:-

But before knowing the process first we should know about the equipments required for rain water harvesting.


Catchment is the surface area where the rain water will fall and from that it is collected. The surface are is generally rooftop area. It may be flat or sloped.

Collection pipe:-

The surface area is connected to pipe. It may be one or more than one depending upon the size of the surface area.

Then filter:-

Different filters are used for filtering the rain water, such as sand gravel filter, charcol filter, pvc filter etc. The basic work is to filter the water.

First flush device:-

It is used to discharge the first rain water collected from the rain water harvesting system. The first rain water may be contaminated as it purifies the air by washing it. So it is better to avoid the first rain water to use.

Storage tank:-

After the water is filtered it is collected in storage tanks.


First the rain water is collected through pipes from the rooftop. Then it is passed through filters to remove impurities. Then it is stored in storage tanks which is used later.

Application of rain water harvesting:-

Rain water collected from rain water harvesting can be used in many works.

Toilet and urinal flushing:-

Toilet and urinal flushing water are used but not directly contacted with human. So it is best to use rain water to that will support to our future requirement of water.


Rain water can be used for gardening which the best use of it. Generally the trees get rain water during rain, but again this water can be stored to use for watering plants when there is no rain.

Washing of cars/ bikes:-

Every one in today’s world are giving priority for using personal vehicle for having speed transportation. So each people have their own vehicle at home whether it is a car or bike. To take are of them we often wash them and use a lot of amount of water which is great wastage of usable water. If we are using rain water instead of municipal water that be a great help to our environment.

Also bus , trucks can be washed off through this.

Rain water harvesting system is a must for commercial buildings. As they use a lot of amount of water.

To know more such topics go through builtifyblog.

Neerain is proud to republish this article for spreading awareness about situation of water, for our stakeholders. Credit whatsoever goes to the Author.

This article is published by: –


We would like to spread this for the benefit of fellow Indians.

Author:   builtify

Publish On: August 21, 2019

Share this: