L.A. Looks at Harvesting Rain Water

LOS ANGELES, March 12, 2005 — -- In the last few weeks, Los Angeles has had more than 35 inches of rain. Most of that water has run straight down to the sea.

"Los Angeles is nearly two-thirds paved," said Andy Lipkis, president of TreePeople, an environmental group. "The land is sealed, so almost all the water that falls runs off. The amounts are stunning."

But TreePeople has convinced the city to invest in a simple idea that goes back to the dawn of civilization -- to catch the rain water in underground cisterns. The first project, a 110,000-gallon tank at a Los Angeles elementary school, has provided enough irrigation water to transform asphalt into green playing fields.

"In economic terms, we no longer have a water bill, in essence," said Robert Burke, principal of the school, Open Charter Elementary.

Trees now shade the buildings at the school, reducing the need for air conditioning.

The system works by funneling rainwater through storm drains into a cistern, where it passes through a filtration unit. That underground treatment unit filters out this witch's brew of sediment, oil, gas, animal waste and trash. A tanker truck comes along on a regular basis, pumps it out and takes it away.

Those waste products would otherwise head right into the Pacific Ocean.

"The oceans become toxic," Lipkis said. "People get sick."

The city is looking into building more cisterns. Given that half of all water in Los Angeles. goes to lawns, a network of cisterns could save enormous amounts of money over time.

In the recent wave of rains, an estimated 80 billion gallons of rain water has been lost to Los Angeles. For a city -- built in a desert -- that imports 85 percent of its water at a cost of $1 billion per year, that is an enormous waste, Lipkis said.

"We hemorrhage 3.8 billion gallons of water when it rains just under a half an inch in Los Angeles," he said.

ABC News' Judy Muller originally reported this story March 6, 2005, on "World News Tonight."