Rooftop Rain Water Harvesting is the technique through which rain water is captured from the roof catchments and stored in reservoirs. Harvested rain water can be stored in sub-surface ground water reservoir by adopting artificial recharge techniques to meet the household needs through storage in tanks.

In this method there are few steps to be followed
Step 1:- clean the surface of roof top so that after collecting water ,it must be fit for usage.

Step 2:- Create channels around roof for collecting water and connect them all with a single pipe.

Step 3:- place a filter at the other end of the pipe ,so that the rest of the impurities gets filtered out .

Step 4:- dig a pit and cover the walls of pit with plastic so that the water does not gets absorbed by the soil.

Step 5:- connect a hand pump with the pit so that the collected water can be taken and used .

this is how rain water harvesting system works . I hope this answer will help everybody in their studies .

Rooftop rainwater harvesting is a technique used to collect and store rainwater that falls on rooftops for future use. It is an effective method to conserve water and reduce dependency on external sources. Here is a step-by-step procedure for implementing rooftop rainwater harvesting:

1. Assess Roof Area:
- Calculate the roof area that can be utilized for rainwater harvesting.
- Consider the size, shape, and slope of the roof.
- Ensure the roof is free from any debris or obstructions.

2. Install Gutters and Downspouts:
- Fix gutters along the edges of the roof to collect rainwater.
- Ensure the gutters are sloped towards the downspouts for proper water flow.
- Use materials such as PVC or metal for durability.

3. Connect Filter and First Flush Device:
- Attach a filter at the beginning of the downspout to remove debris and leaves from the water.
- Install a first flush device that diverts the initial dirty rainwater away from the storage tank.
- This helps in improving the quality of harvested water.

4. Storage Tank Installation:
- Select an appropriate location for the storage tank near the downspout.
- Ensure the tank is made of non-toxic material like plastic or concrete.
- Connect the downspout to the storage tank using a pipe.

5. Overflow Arrangement:
- Set up an overflow arrangement to divert excess rainwater when the tank is full.
- Connect the overflow pipe to a drain or a recharge pit to prevent waterlogging.

6. Filter and Purification System:
- Install a filtration system to further purify the harvested rainwater.
- Utilize methods like sand filters, activated carbon filters, or UV sterilization.
- Ensure the water is safe for the intended use.

7. Distribution System:
- Connect a pump to the storage tank for easy retrieval of the harvested water.
- Install a separate pipeline to distribute the water to various areas of use.
- Use valves and control systems to regulate the flow of water.

8. Maintenance and Cleaning:
- Regularly clean the gutters, filters, and storage tank to remove any accumulated debris.
- Inspect the system for any leaks or damages and repair them promptly.
- Monitor the water quality periodically and take necessary actions.

Remember to check the local regulations and guidelines before implementing rooftop rainwater harvesting. With proper installation and maintenance, this technique can provide a sustainable source of water for various purposes while promoting water conservation.