One of the most striking features of the Lady Bird Johnson Wildflower Center in Austin,
Texas, is the rainwater harvesting system, which includes a handsome native-limestone aqueduct,
cistern, and ponds that collect and store more than 10,000 gallons of water for every inch of
rain that falls. Such an extensive system is an expensive, long-term investment, but a simple
rain barrel in your own back yard is an easy, inexpensive way to conserve water by capturing
rain from downspouts.
Rain barrels and rainwater collection systems allow you to save rainwater to use at your
convenience instead of watering the garden with tap water. If you live in an area where
watering is restricted, a rain barrel gives you the flexibility to water any time. Rainwater is
softer than city water, and it doesn’t contain chlorine, fluoride, or other chemicals: plants
thrive on rainwater. Rain barrels also help limit runoff, reducing pressure on storm-water
drainage systems systems.
Collecting rainwater is as simple as diverting water from a downspout into a vessel. It only
takes about one-fourth inch of rain to fill a typical 50-gallon barrel. Rain barrels are
usually installed with a diverter, to send water from the downspout into the barrel. When the
barrel fills up, water runs through the downspout as usual, and the overflow area is often an
ideal spot for a rain garden. Some diverters are fitted with a filter, to keep leaves and other
debris from getting into the barrel; all rain barrels should have a mosquito screen.
Rain barrels typically have a spigot for filling a watering can or a place to attach a hose,
or both. Since gravity drains the barrel, a hose attachment is usually at the bottom of the
barrel. A 50-gallon barrel full of water weighs 400 pounds, so find a level spot and raise the
barrel on a couple of cinder blocks to create a little clearance for the spigot and to keep it
from settling in wet soil.
Home-garden irrigation amounts to about 40 percent of residential water use. With a full
rain barrel, you can water all the planters on the porch or patio, refresh the zinnias and
sunflowers in the sunny flower bed nearby, and still have enough to water them all again a few
days later, without turning on a tap.