"In Las Vegas, water used indoors travels a continuous loop. From homes, water flows to a treatment plant, which sends it back to Lake Mead. Then an equivalent amount is pumped from the lake, and the 12-mile journey to treatment plants and Southern Nevada's taps begins again.
The Southern Nevada Water Authority wants that system preserved because it allows Las Vegas to consume more than its annual 300,000-acre-foot allotment from the Colorado River. Water returned to the lake converts to credits that the Water Authority can use to pump more water from the lake.
But some homeowners, builders and environmentalists watching this continuous loop wonder: Why not shorten the distance water travels by allowing homes to keep and recycle the water they use - what's known as graywater? The water authority, after studying the idea, decided this year to make it official policy to oppose it."