Rain on a roof

How to Harvest Rainwater

They’ve been used for centuries where and when rains are absent. Today, in the face of persistent drought and depleted aquifers, rainwater harvesting makes more sense than ever.

No matter how it’s collected or what it’s used for, utilizing rainwater lessens the pressure on our water supply. Collecting rainwater is appropriate in desert climates with monsoon seasons or infrequent thunderstorms as well as regions with adequate rainfall. Like solar-generated electricity stored in a battery, harvested rainwater is there when you need it.

Thanks to new filtration and treatment technology, sophisticated rainwater systems are designed to supply the water needs, including drinking water, of entire households. These systems are particularly appropriate to rural dwellers whose wells may be brackish or contaminated by agricultural runoff, and city folk whose municipal water systems draw from polluted sources.

Most home-harvested water is used to irrigate landscapes. Outdoor use of water, much of which goes to lawns and gardens, accounts for nearly a third of household water used in the United States. the Environmental Protection Agency says that nine billion gallons of water a day are devoted to landscape irrigation.

Collection strategies are of two types. Passive systems are designed to collect and direct runoff where it’s needed, allowing it to soak into the ground around trees, in irrigation troughs, or in holding ponds that support rain gardens.

Active Systems collect and channel rain into holding vessels. These can be as sophisticated as collecting runoff from the roofs of large commercial structures in underground cisterns or as simple as a garbage can placed under a home’s rain gutter. Small improvements on this simple roof-and-barrel method can result in more rainwater collected and better delivery systems.

Houses with existing gutters already have a suitable method of transporting rainwater to the ground. Rain barrels with lids that accept standard drain pipe sizes can be fitted under downspouts for maximum collection. Barrels can be connected in a series, at the bottom, to increase capacity.

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