And that's just the average of students enrolled from the first day of school to the 40th day. The actual enrollment on the 40th day of school was even higher, at 24,936, Dickson said.

"We anticipated an increase of about 1,000 students, and this is obviously a little more than what we thought," she said. School systems make a difference when young families look for homes. But certain areas are unaffordable for many families just starting out, said Patti Salvage, broker and manager of RealtySouth Inverness.

Not Shelby County. New neighborhoods aimed at first-time home buyers and young families with children are being built in just about every part of the county.

"Parents are savvy enough these days to know which school systems are considered good and bad," Salvage said. While real estate agents aren't allowed to steer potential buyers toward a certain area based on a school district, most come to the agent with that knowledge already, she said.

And families know they can get more house for their money if they go farther out from Birmingham, Salvage said.

A lot of those families can't afford to live in Mountain Brook, Homewood or Vestavia Hills, whose schools boast some of the state's highest scores on standardized tests, but they can afford to move to Shelby County, a top performer among Alabama's county school systems, Salvage said.

Houses ranging in price from $120,000 to $250,000 are being built all over the county, especially in areas such as Chelsea, Calera and Alabaster.

"I can remember when Pelham had new subdivisions coming in and we were thinking, `Oh, we're really getting out there,'" Salvage said. "Now we're into Montevallo."

While Shelby County officials welcome the growth, Superintendent Evan Major knows that it brings more children and a need for new schools.

"The bottom line is that developers are going to build to accommodate the market, and the market right now is for young families," Major said. "And what we're seeing is that once a family lives here, they stay here. Our problem is, how do we continue to provide capital outlay to accommodate the kids? Where do we get money to build new classrooms and new schools?"

Instead of building, the system recently has added trailer classrooms and teachers to keep up with the growth.

So far this school year, the system has added 35 trailer classrooms to the 64 that already were in use. Major said he expects to add about 40 next school year.

"Shelby County has been designated as the No. 1 place to raise kids in the state," he said. "It's a good place to live and work, we have good churches and good schools, and we will continue to grow for as long as I can see into the future."