Not too long ago, Heber City and the surrounding Wasatch County was a sleepy mountain community know for its hot springs and Swiss Days festival.

But as commuters to the Wasatch Front and Summit County have been drawn by the area's relatively affordable housing and outdoor recreation, subdivisions are rising and big-box retailers are eyeing the now bustling county.

"I guess we've been discovered," said Al Mickelsen, the county's director of planning. "People come out here to recreate and want to stick around, and they buy. ... It's a challenge. We're losing the identity of the small town feel."

That growth has also made Wasatch County the fastest growing in the state, with a one-year growth rate of 6.5 percent grew to 20,255 people from July 1, 2005 to July 1, 2006, according to U.S. Census Bureau estimates released today.

That surpasses Washington County, which grew by 6 percent to 126,312, according to the estimates. Washington County, which last year ranked fifth nationally in growth this decade and has now fallen to 19th nationally with just under 40 percent growth since 2000.

However, Utah demographers aren't so sure. They say the Census Bureau continues to underestimate Utah's population, including Washington County.

Estimates released earlier by the Utah Population Estimates Committee show Washington County remains the state's fastest-growing county, with a 2006 population of 134,899.

"They are pretty close to our estimates for Wasatch County, but they are way low for Washington," said Pam Perlich, senior research economist at the University of Utah's Bureau of Economic and Business Research.

Unlike in prior years, national rankings were based on growth since 2000.

Even though Washington County has seen a drop in the number of new housing permits, its growth remains "enormous," said Robert Spendlove, manager of demographic and economic analysis for the Governor's Office of Planning and Budget.

"Six percent growth with 130,000 population is still very, very large growth," Spendlove said. "As an area becomes larger it's more difficult" to maintain high rates.

Meanwhile, Wasatch County is expecting to surpass the 300 new home permits it issued last year. Roads are becoming a key planning concern as traffic increases, Micklesen said.

Still, the rural feel is being maintained by allowing only one home per acre in unincorporated areas. Developers are also generally required to build affordable housing within their projects, he said.