U.S. Suburban Sprawl, by the Numbers

The latest data from the U.S. Census Bureau reinforce a vision of the United States where population growth and suburban sprawl will have to confront serious water shortages in the years to come.

Nine of the 10 fastest-growing counties were located in the South or West, with water-stressed areas like Phoenix, Atlanta and parts of Texas among the leaders.

A whopping 102,000 people moved to Maricopa, Ariz., between 2006 and 2007, capping a period of rapid expansion that has seen more than 800,000 people move in since 2000. Nearby Pinal County, Ariz., has seen its population increase by two-thirds since 2000.

Phoenix, like much of the Southwest, relies on massive dams and aqueducts from the Colorado River to remain viable. Meanwhile the desert region has been suffering through a decades-long drought. One recent study predicted that Colorado River reservoirs could run dry in less than 15 years – not enough time to pay off the mortgage on all those new homes. Clark County, near Las Vegas, Nev., which also relies on the Colorado River, also made the list of 10 fastest-growing counties by sheer numbers, with 461,000 new residents since 2000.

Atlanta, too, has been sprawling outward, with three suburban counties making the nation's top 10 list for fastest rate of population growth since 2000, with population growth between 56% and 62%. The Southeast has confronted an historic drought in the past year, and some long-term projections say global warming could result in the traditionally wet region being starved for water in the coming decades. The demand for water has prompted Georgia to fight Alabama and Florida for rights to some river systems, and Tennessee for others.

North Carolina, which has also been touched by the same drought, is seeing notable growth around Raleigh and Charlotte, where surrounding counties saw list-topping numbers for population growth in the last year of data, with more than 30,000 people moving into each.

The fastest-growing region of the country by some measures, the Dallas-Fort Worth area of Texas, is also staring at a looming water crisis, according to some projections. "In short, demand is projected to grow faster than supply," a 2004 North Texas Future Fund report states. "By the year 2010, the deficit could be 272,000 acre-feet, and by 2050 the deficit could reach 1.1 million-acre feet per year — an amount greater than total current demand."

Below is a Census chart showing some more data. For more numbers, click here.

U.S. Census