The estimates released Monday by the state's leading demographers show significant growth in the Jordan, Davis, Alpine, Tooele and Washington districts, in particular. Statewide, the student population grew an estimated 2.9 percent, to a total of 510,012 students.

The growth in part can be attributed to a spurt triggered by baby boomers' grandchildren starting their own families, said Patty Murphy, the Utah Office of Education economist. In-migration also is a factor.

Utah had expected about 2,000 new students to move in from out of state, when in reality, about 6,000 did, Murphy said. "Nobody anticipated the housing boom to this extent and no one predicted the timing of it, either."

The new student growth may mean per-pupil funding in Utah schools will drop in the upcoming budget year if the Legislature doesn't free up new funds, Murphy said, adding that Utah already has the lowest per-student funding in the nation.

In the Davis School District, enrollments grew an estimated 1,850 students, mostly in elementary schools in high-growth areas such as Kaysville and Farmington, district planner Chase Rogers said.

''Some people might say, 'Of course there are more students, look at all the new housing.' The reality is that we have the same number of new homes constructed this year as last,'' he said. But ''the families we had move in this year, to both new and existing homes, have more school-age children than we have seen in the past,'' he said.

Davis High School in Kaysville had so many more 11th-graders than expected that the district had to hire extra teachers and teaching assistants to help manage classrooms.

In June, the district will hold an election asking voters for permission to bond to build new schools throughout the district.

Other areas, such as Washington School District, were more prepared for the growth because their population has boomed consistently for the past few years.

Even though Washington predicted more than 6 percent growth rate it ended up with, one elementary school had to run double sessions. A new elementary will open in January, said Marshall Topham, assistant superintendent for secondary education.

The district plans to open or renovate five schools in 2006, and another five in both 2007 and 2008, when a new high school will be built. Topham hopes the current area high schools, which are nearing capacity, can last that long.

"The elementary did catch us off guard a little bit," Topham said. "But we are surviving in secondary schools, and we haven't had overcrowded classrooms."

Washington's biggest challenge has been finding contractors to complete the construction work.

That hasn't been a problem for Alpine School District, which built two junior highs and eight elementaries after passing a $200 million bond in 2001. The district has seen a total growth of 7,608 students in the past six years, which falls within the district's predictions, spokeswoman Jerrilyn Mortensen said.

"We continue to grow, and we're currently looking for ways to house future growth and provide for future needs," she said.

In addition to growth in most school districts, charter schools nearly doubled their populations from 6,237 to 11,528 students. The growth may be due in part to the fact that students who previously were home-schooled are now attending charter schools, Murphy said.

smcfarland@sltrib.com