Home Buying

Residential Rainwater Harvesting System

26 JUN 2024

The significance of water can never be emphasised enough, because it’s the very reason why life exists on the planet. The scarcity of water in different parts of India has become an alarming concern, which is why homes today have taken the initiative to conserve water. In apartment buildings, where water usage is high due to multiple families, builders now include residential rainwater harvesting system. These systems collect rainwater from rooftops and surface runoff, directing it into underground tanks. The collected water serves non-drinking purposes, especially during water scarcity periods.

What is Rooftop Rainwater Harvesting?

Residential rainwater harvesting system
As the name suggests, the Rooftop Rainwater harvesting system means collecting and storing rainwater that falls onto the roofs of buildings. It involves installing a system of gutters, downspouts, filters, and storage tanks to capture rainwater before it runs off into the ground or stormwater drains. After proper filtration, people can use this collected water for various purposes, including watering gardens, flushing toilets, and even drinking. Rainwater harvesting systems (RRWHS) can be set up in any building with a roof and enough space for a tank or to replenish groundwater through a borewell. It is important to note that, your rainwater harvesting system requires regular upkeep. Make sure to clean drain pipes and gutters periodically, clearing out any debris to keep the mesh free from blockages. Also, maintain a clean rooftop to prevent debris buildup.

How to do Rainwater Harvesting in Apartments

Rainwater harvesting in building is becoming more and more crucial for conserving water, especially in apartments and this in turn can lead to big savings. One of the most effective methods of rainwater harvesting for apartments is the rooftop rainwater harvesting system. In this system, channels or gutters guide the rainwater that falls on the apartment roof to storage tanks or recharge pits. Downpipes are connected to the gutters to move the rainwater from the roof. You should also ensure that the gutter size matches the flow during heavy rain. The stored water is then used for gardening, washing cars, cleaning paths, and more, or you can save it for later.

Benefits of Rainwater Harvesting in Apartments

These days, apartment builders in Kerala are investing in sustainable technology like rainwater harvesting to save water. Let’s look at some benefits of this:

You lead an Eco-friendly life

The ultimate aim of rainwater harvesting technology is to save water and energy. Apartments that implement these features have a sustainable foundation that allows residents to lead a quality and eco-friendly life. Installing a rainwater harvesting system can cut water use by 40% or more, making it handy for other tasks. With so many relying on groundwater, it’s getting strained. Rainwater harvesting steps in to help. Since harvested rainwater is clean and can flush out salt from plants and soil, it’s perfect for gardening, and enhancing apartment landscapes.

Good Supply of Water

Rainwater harvesting system in apartments will be able to supply a good amount of water. This system serves as a reliable source of water, particularly crucial during the summer season when water demand typically surges. Additionally, it provides a valuable backup supply during periods of water scarcity or shortages, ensuring continuous access to water for residents’ needs.

Reduction in Cost of Water Bills

Rainwater harvesting can help you save a lot of money on water bills. It conserves water and reduces the need for municipal water, cutting down your monthly bill. People who live in an apartment that is well equipped with a rainwater harvesting system, end up saving up to 40-50% on their water bills. One can use the water for washing machines, gardening, bathing, etc.

Low Maintenance

Rainwater harvesting brings the benefit of low maintenance. It only involves collecting, filtering, storing, and using rainwater for different purposes for your daily chores. The system is affordable, easy to set up, and needs minimal upkeep. If integrated during building construction, installation costs are even lower. Some common methods include Barrel harvesting, Dry system, Wet system, and green roof, each with varying costs based on techniques and materials.

Suitable for Irrigation

Harvesting rainwater requires minimal infrastructure. Often, just using rooftops is enough to collect rainwater, which is great for the environment. Unlike fuel-based methods, it doesn’t pollute or waste fuel. Rainwater lacks the chemicals found in groundwater, making it perfect for irrigation. It’s handy for watering plants and gardens, especially when you need lots of water for big areas like lawns and parks. Rainwater harvesting is especially helpful in areas prone to forest fires during hot, dry spells.

Purpose of Utilizing the Harvested Rainwater

Water is one of the most precious resources that plays a very important role in our daily chores. From drinking and bathing to watering plants and cooking, water is almost part of everything in our lives.


After undergoing treatment, rainwater becomes suitable for bathing or showering for both people and pets. Chemical treatment is commonly used to eliminate harmful bacteria from rainwater. Additionally, boiling the water is an effective method to remove impurities, ensuring clean and warm bathing water as a bonus!

Cooking and Drinking

Rainwater can indeed be used for drinking and cooking, but it’s essential to take precautionary measures to ensure its safety. Rainwater when collected properly and treated appropriately, can be safe for consumption. However, it’s crucial to filter and purify the water to remove any potential contaminants before using it for drinking or cooking purposes. This may involve using filtration systems, UV treatment, boiling, or chemical disinfection methods to ensure that the rainwater meets the necessary quality standards for human consumption.


Using rainwater for washing clothes is possible, but you need to ensure the water is clean and safe enough to wash. First, you need to filter out the water to remove any pollen, dust, or mould. After filtering, the water is technically safe for washing. However, you might want to make sure there are no harmful bacteria left. Chlorine can help with this, but it needs to be handled carefully. Chlorine evaporates quickly, so you can simply add it to the tank and leave it uncovered for some time to ensure it’s safe to use.

For Toilets

Using rainwater to flush waste in toilets helps conserve freshwater resources. Instead of diverting treated drinking water for flushing toilets, people can divert rainwater harvested from rooftops or other surfaces to toilet cisterns. This reduces the demand for municipal water supplies and can lead to significant water savings, especially in areas where water is scarce or expensive. Additionally, using rainwater for flushing toilets can also help reduce the strain on sewage systems and wastewater treatment facilities.

Watering Plants

Whether you have a sophisticated in-ground irrigation system or simply use a hose and sprinkler, the rainwater you collect can be utilized to water your lawn or garden. Instead of relying solely on freshwater from municipal sources, you can harness the natural bounty of rainwater to nourish your plants and keep your outdoor spaces green and healthy.

Different Methods of Rainwater Harvesting

Surface Runoff Rainwater Harvesting Method

Surface runoff rainwater harvesting is a way of gathering rainwater that flows along the ground during rainfall. This water is collected in an underground tank for uses like irrigation. To conserve water effectively during storage, it’s crucial to minimize evaporation. This method is simple to adopt and can be quite beneficial if used wisely. Its main goal is to fulfill the growing need for water, while also reducing water pollution, soil erosion, and road flooding.

Rooftop Rainwater Harvesting Methods

Rooftop rainwater harvesting is a way to collect rainwater directly from rooftops. Houses or buildings capture rainwater from their roofs and store it in tanks. People can then store this harvested rainwater in tanks or direct it to recharge systems to meet household or commercial needs. It’s a simple, eco-friendly, and cost-effective method. The main goal is to make water available for future use and improve groundwater quality.


Residential rainwater harvesting system in buildings represents a simple yet powerful solution to some of the most pressing challenges facing our planet today. Many apartments you find today are taking the route of sustainability and reducing the dependence on freshwater resources. At Confident Group, we understand how pious our natural resources are, and the pressing challenges faced by our planet. which is why we implement rainwater harvesting systems in our projects to support a green future.

Author - Webdura


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