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Rainwater Harvesting – Need, Advantages and Disadvantages

Last Updated : 10 Nov, 2023
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Rainwater harvesting refers to the process or technology that is used for the conservation of rainwater through the collection, storing, and purifying of the rainwater that runs off from rooftops, parks, and other uses. All living organisms including plants, animals, and humans need water to live and carry out different cellular activities.


Rainwater Harvesting

Can you imagine a day without water?

We cannot imagine a day without water, as water is used for different kinds of activities every day, including drinking, cleaning, washing, bathing, and industrial uses. Water is very precious and also essential for both biotic and abiotic components of the ecosystem. Due to a lack of proper water conservation and pollution of water bodies, water is scarce.

How to Harvest Rainwater?

The major components which are essential for rainwater harvesting systems include the following:

  1. Catchment: The catchment is used for the collection and also for storage of the captured form of rainwater.
  2. Conveyance system: The transportation of the harvested water from the catchment to the recharge zone is done by this system of conveyance.
  3. Flush: The first spell of rain is flushed out from it.
  4. Filter: The filter portion of the system is used for the collection of rainwater and the removal of pollutants.
  5. Tanks and Recharge Structure: This is used for the storage of filtered water which is ready to use.

The process of rainwater harvesting is the collection and also storage of the rainwater, which runs off naturally or from man-made catchment areas like rooftops, compounds, rock surfaces, and so forth.

Several factors play important role in the water harvested. Some of the important factors are as follows:

  1. Amount of runoff
  2. Features of catchments and catchment areas.
  3. Impact on the environment
  4. Technology available
  5. Capacity of the storage tanks
  6. Types of roof, slope and materials
  7. Amount of rainwater collected.
  8. Speed of rainwater penetration to recharge groundwater.

Why do we Harvest Rainwater?

We harvest rainwater for following purposes:

Water Crisis

The problems of the water crisis, which has been increasing over the years in different parts of the world and India, can be tactfully tackled by rainwater harvesting. This is particularly useful in hilly areas, where it can be used for domestic uses, and also in remote areas, where surface pollution is less comparatively and hence rainwater harvesting is ideal.


Rainwater distribution is not equally distributed over space and time, and many of the crops are more water-demanding. Hence, the unavailability of water of equal quality and quantity would cause drastic problems. Hence, rainwater harvesting could help in this process of unequal water distribution.

Bad Monsoon

Bad monsoon or less monsoon can lead to low crop yield and a shortage of food. Even flora and fauna also suffer from the same. Farmers are most affected by bad monsoons and hence rainwater harvesting is the ideal solution for them.

Alternative for water supply in Dry areas

It can work as a good alternative source of water for the backup of the main supply of water in areas prone to dry spells and it can be used by the community. It can help in irrigation and also work as a cost-effective method.

Stored for Future Use

Stored rainwater is used for revitalizing groundwater level and also for improving its quality. Hence, it helps in checking surface runoff and also reduces incidents of soil erosion.

Advantages of Rainwater Harvesting


Benefits of Rainwater Harvesting

The advantages of rainwater harvesting are as follows:

  1. Rainwater harvesting is one of the most cost-effective, and very easy to maintain systems. The cost of the foundation of rainwater harvesting structures is quite less than other pumping structures.
  2. Rainwater Harvesting is an environment-friendly method and minimizes the impact of floods by rushing water to larger tanks for recycling and helps in the reduction of the pressure on drainage.
  3. It prevents soil erosion and also reduces the flow of storm water in order to prevent urban flooding around the buildings.
  4. Rainwater collection helps to mitigate droughts and since they are mostly free of harmful chemicals and substances, it is suitable for irrigation.
  5. Groundwater levels are increased and improved quality wise.

Disadvantages of Rain water Harvesting

With advantages, come some disadvantages of rainwater harvesting. Some of them are mentioned below:

  1. It requires regular maintenance. Otherwise, the purity of the water can be missed out.
  2. Technical skills are required for the installation and working of the mechanism; otherwise, it becomes a little tiresome.
  3. With irregular rainfall in India, it can limit the supply of rainwater.
  4. If the installation is not done in the correct format, it can lead to the breeding of mosquitoes and may increase waterborne diseases.
  5. There is a certain limit for storage of the water, if it exceeds the limit, it can lead to an overflow of water; ultimately affecting the infrastructure around

Methods of Rain water Harvesting

The two most commonly used methods of rainwater harvesting are:

Surface Runoff Harvesting

This is one of the most suitable forms of rainwater harvesting in urban spaces. This can be stored and used in the future. The water gets stored into storage tanks which are present below the ground.Insufficient availability of water can lead to problems in both domestic and sanitation areas leading to environmental pollution. This could be prevented by storing surface water and also directing its flow towards small creeks and, into reservoirs.

Rooftop Rainwater Harvesting

Rooftop rainwater harvesting is a technique for catching rainwater where it falls, capturing it from the roof catchments of residential or commercial buildings, and storing it in tanks. To satisfy the demands of the household or business, harvested rainwater can either be transferred to an artificial recharge system or kept in tanks. Making water available for future use, enhancing the quality of ground water, and other goals are the primary goals of rooftop rainwater harvesting.

FAQs on Rainwater Harvesting

What is the Importance of Rainwater Harvesting?

Rainwater harvesting helps to reduce soil erosion and floods by collection of the rainwater. The process of rainwater harvesting aims to overcome the problem of water scarcity.

What is Rainwater Harvesting?

Rainwater harvesting refers to the collection and also storage of rain water which runs off from roof tops, parks, open grounds, roads and so on.

What is the conclusion of rainwater harvesting?

The rainwater harvesting helps to improve the use of water available from precipitation and also run off by the concentration of it for immediate usage and also storage.

What are the objectives and advantages of Rainwater Harvesting?

Some advantages of rainwater harvesting system are:

  • It helps in conserving water
  • Groundwater level increases
  • It is cheap and easy to maintain
  • It is a good examples of reuse of water
  • It reduces soil erosion

What is the main purpose of rainwater harvesting?

The main purpose of rainwater harvesting is to increase the groundwater level.

What are the Factors Affecting the Amount of Rainwater Harvested?

Some important factors affecting the amount of rainwater harvested are:

  1. Features of the catchments.
  2. Availability of the technologies.
  3. Capacity of the storage tanks
  4. Types of roofs and their slopes.

What are the Different methods of Rainwater Harvesting?

Two important methods of rainwater harvesting are as follows:

  1. Surface runoff harvesting.
  2. Rooftop Rainwater harvesting

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