Maybe, as some predict, fresh water will become the next oil in terms of being a necessary but limited resource. However, even if that turns out to be hyperbole, regional droughts will always be with us. That means that at some point many people will be forced to conserve water.
"The population is growing, but the water supply is not," says Bill Hoffman, a coordinator for the City of Austin Water Conservation Program, in Texas. That's why people around the country are turning to the centuries–old practice of collecting rain as an alternative source of water.
By collecting rain from a roof during wet months and storing it in a tank or cistern, homeowners can create an alternative supply that won't tax the groundwater or jack up the water bill.
And because rain doesn't contain the minerals found n wells or the chlorine in municipal supplies, it's ideal for watering the lawn, washing the car, doing the laundry, taking a shower—even drinking if it's properly filtered.
"Rainwater is the purest water you can find," says Dr. Hari Krishna, president of the American Rainwater Catchment Systems Association (ARCSA).
A rainwater-collection system can be as simple as a rain barrel at the end of a downspout or as elaborate as a whole–house system, which supplies all the water needs for my family of four in the Texas Hill Country. Cost and complexity depend on how much water you need and how you plan to use it.
A simple system is adequate for landscaping needs, but cost, complexity, and maintenance increase if you're planning to drink rainwater or pipe it into the house. Check with your local building official about the regulations on rainwater systems for indoor use—codes differ widely from one community to another.
A house with a sloped roof, gutters, and downspouts is well on its way to harvesting rainwater for landscape irrigation or other nonpotable uses. You just need a few simple components: wire–mesh gutter screens to keep out debris, a storage tank, and a way to move the water out of the tank.
The storage tank, or cistern, can be made from almost any material—even a clean recycled metal drum. Gardening stores sell 55– to 75–gallon plastic rain barrels, complete with leaf screens and spouts, for $50 to $250. Wooden barrels have a nostalgic charm, but they're hard to come by and expensive. A wine or whiskey barrel made by a professional cooper will cost at least $250.
Larger storage tanks can be made of stone, cement, metal, wood, or fiberglass.
To prevent mosquitoes from breeding in tanks, make sure the tanks are covered or screened. Also, during winter months, barrels should be kept only three quarters full to allow freezing water to expand.
Gravity is the easiest (and cheapest) way to move rainwater out of the tank. Systems that work by gravity are good for watering landscapes; you only need to open a spigot or valve at the bottom of the tank. However, if you have to move water to a level higher than the tank, you'll need a pump.
A 1–horsepower electric jet pump mounted in a small shed near the tank costs about $400, and can provide about 8 gallons of water a minute up to 500 feet away from the water tank.
