They simply couldn't afford to live in the booming southwestern Utah community.

"A number of teachers and administrators have just bowed out," said Assistant Superintendent Marshall Topham. "Property values have skyrocketed, taking teachers right out of the market."

The sudden difficulty in hiring educators is one of many consequences of the county's rapid growth, which has landed it on a newly released list of the 100 fastest-growing counties in the nation.

The U.S. Census Bureau report released Thursday includes three Utah counties - Washington, Tooele and Wasatch.

The fastest-growing county in the nation is Loudoun, Va., near Washington, D.C., which recorded a 41 percent population increase from April 1, 2000, to July 1, 2004.

Tooele County came in at No. 33 with a 22 percent jump during the same period, followed by Washington County (No. 37) and Wasatch (No. 53).

Officials from these counties are well aware that rapid growth has swelled local classrooms, strained water and sewer systems and spurred accelerated construction. In fact, Washington County leaders and state demographers say the census has underestimated the county's growth by about 7,000 people.

State figures say Washington County has a population of 117,000 with a large number of the residents living in the St. George area, while the Census estimates there are 110,000 residents.

The disparity comes from the different methods used by Census Bureau and state officials to determine population.

The Census primarily tracks tax returns and payments through the Internal Revenue Service. The state uses these figures, but checks them against school employment, building permits and the membership rolls of The Church of Jesus Christ of Latter-day Saints, according to Robert Spendlove, manager of the state's Demographic and Economic Analysis Office.

State numbers peg Washington County as the fastest growing, followed by Wasatch and Tooele.

Washington County Commissioner James Eardley says an additional 20,000 residents have moved in during the past four years. The influx has created "a mixed blessing," said Eardley, by increasing the burden on transportation planners and public safety officers, while simultaneously creating new jobs and prosperity.

"We are seeing opportunities for our young people to stay home, which we didn't always have," Eardley said. "They used to have to go to Las Vegas and Southern California to find jobs."

Now, people from Las Vegas and Southern California are flocking to Washington County, where they see the homes as a bargain, said Paul Herbert, a real estate agent. And their migration is creating a housing shortage.

"There are not enough homes to sell, especially in the under-$250,000 price range," Herbert said. "Obviously, if you own real estate or you are a seller, it is a good thing."

But it's not so good for school districts, according to Topham.

New teachers get paid $25,000, while an acre of land alone costs about $100,000.

The rising population has created other problems for the district as well. Some 1,500 new students enrolled in local schools this year - double the 4 percent growth rate anticipated - driving class sizes up to about 28 students per teacher.

"It is hard for people to assimilate how much growth is actually going on here," he said. And that growth isn't going to slow any time soon.

The state projects Washington County's population doubling, to 250,000, by 2020 and more than doubling again by 2050, surpassing 600,000.

mcanham@sltrib.com