Rainwater harvesting (RWH) is the collection and storage of rain, rather than allowing it to run off. Rainwater is collected from a roof-like surface and redirected to a tank, cistern, deep pit (well, shaft, or borehole), aquifer, or a reservoir with percolation, so that it seeps down and restores the ground water. Dew and fog can also be collected with nets or other tools. Rainwater harvesting differs from stormwater harvesting as the runoff is typically collected from roofs and other surfaces for storage and subsequent reuse. Its uses include watering gardens, livestock, irrigation, domestic use with proper treatment, and domestic heating. The harvested water can also be committed to longer-term storage or groundwater recharge.
Rainwater harvesting is one of the simplest and oldest methods of self-supply of water for households, having been used in South Asia and other countries for many thousands of years. Installations can be designed for different scales including households, neighbourhoods and communities and can also be designed to serve institutions such as schools, hospitals and other public facilities
What are the benefits of rainwater harvesting?
Rainwater harvesting provides many benefits to your home, your wallet, and the environment.
- Can save you money on your water bill. Rainwater is an excellent tap water alternative for water-heavy outdoor uses, such as washing cars and gardening. This rainwater can save you money each month on your water bill, allowing your rainwater harvesting system to pay for itself over time.
- Benefits the environment. Rainwater runoff contributes to soil erosion, a phenomenon that disrupts ecosystems and compromises the ability to grow crops. By collecting rainwater before it becomes runoff, you can curb the effects of soil erosion.
- Better than tap water for certain uses. While stored rainwater is not potable without filtration, it is better for certain applications than tap water. For example, the chlorine in tap water can eat away at your car’s paint and kill beneficial bacteria in soil. Rainwater, on the other hand, does not contain the treatment chemicals that tap water possesses. As a result, rainwater is better for washing cars and gardening than tap water.
- Can provide water during times of drought. If you live in a drought-prone region, collecting rainwater can provide additional water when restrictions are put in place. When connected to appropriate water treatment systems, rainwater can be used for potable applications inside the home.