What Is Rainwater Harvesting?

What Is Rainwater Harvesting?

Capture the rain and put it to good use

By Robert Ferguson

Woman collecting water from rainwater storage tank
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Capturing, diversion and storage are the three basic functions of rainwater harvesting. The main purpose of capturing rainwater is for lawn and garden irrigation. This can lower the amount of municipal water that you use. Even if your water comes from a private well, rainwater uses no electricity. Because the rainwater is not treated, it should only be used for your lawn and plants. There are two significant benefits of rainwater harvesting: One is that you utilize an otherwise wasted resource, which is good for the environment because it lowers the carbon footprint. The other is that you save money on your water bills because rainwater is free and plentiful in many areas.

Roof types

Homes or buildings with metal roofs or asphalt shingles provide the best means for harvesting rainwater. The rain flows down the roof easily and is channeled into gutters connected to the rain barrels. Sloping roofs are the best for rainwater collection because they allow the water to easily roll off of them and into their capture buckets.


Store the harvested rainwater in rain barrels or cisterns. Place them under a gutter's downspout to collect the rain. The best rain barrels are made of plastic. Other materials used to make rain barrels include aluminum and fiberglass, though other bins, such as whiskey or wine barrels, can be used as rain barrels if they're treated properly.


Rain gutters provide the distribution needed. They use gravity to distribute the rainwater into barrels or containers. Install a hose bib and garden hose to the rain barrel to use for irrigation. In larger applications, pumps can distribute the collected rainwater to different areas.


Mosquitoes can spread serious diseases such as West Nile virus and malaria. Mostly, they're annoying and keep you from being able to stay outdoors. So you need to make sure your barrels are not breeding grounds for mosquitoes. Tightly cover any container used to collect the rainwater. Keep pets and children away from any still water to prevent them from coming into contact with any bacteria.


Filtering harvested rainwater removes unwanted particles. Use a simple filter placed in the distribution line. Gutter guards or screens can help filter out leaves and other unwanted debris.

The Green Factor

Conserving our planet's natural resources is important now more than ever. With the population ever growing, conservation on all levels is imperative. Every little bit helps.

About the Author

Robert Ferguson is a licensed building contractor with more than 30 years of experience, focusing primarily on residential remodeling, repair, renovation and construction.

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