The district's goal is to have elementary school populations somewhere between 600 and 700 students.
"You always want a small enough school where you're able to support the kids. With that (smaller) population, you can get to all the classrooms, you can have assemblies," said Superintendent Parvin Ahmadi, adding that otherwise, "It gets difficult to know the kids, (and) these are young kids."
Higher populated campuses, Ahmadi said, create logistical problems, such as additional times for lunches and having to have multiple assemblies. That's in addition to issues around picking up and dropping off students, which can be time-consuming even at smaller schools in the city.
"Parents love the size when it's 500 to 600, 700 kids," she said.
Some recent studies have indicated that student learning is negatively impacted in schools with populations of less than 400 students or more than 900 students.
In a 2010 piece in The New York Times about the closing of elementary schools in Kansas City, several experts said campuses with a population of 600-900 students were best for learning.
The "small school effect" was discovered in the 1960s, according to Herbert J. Walberg, university scholar at the University of Illinois at Chicago and an education task force member. Walberg said research in 25 states has shown that "smaller schools produce higher academic achievement than larger schools."
Beyond the educational impact, Ahmadi said the Pleasanton district has a goal of creating schools that children can walk to. "We want kids to stay where they're at, in their neighborhood," she added.
Six elementary schools in Pleasanton are above the district's target. As of Jan. 31, Donlon had 800 students, Fairlands had 754, Hearst had 721, Lydiksen had 712, Walnut Grove had 710 and Mohr had 707.
The most immediate need is in the north, where Donlon, Fairlands, Lydiksen and Walnut Grove are all above the desired population.
Other school districts don't necessarily follow the goal of having 600-700 students. The neighboring San Ramon Valley school district, for example, just broke ground on an elementary school in the Dougherty Valley that will house an estimated 830 students upon its completion in 2015.
"Some school districts have all sizes of elementary schools," Ahmadi said. "That has to do with development and the districts' goals."
Some districts may choose to build larger or smaller schools to support particular programs, such as magnet schools, which emphasize a particular curriculum.
Development is likely to be the most significant factor in Pleasanton. While Donlon, Fairlands, Lydiksen and Walnut Grove all already have more than the district's student population goal, they could also see an influx of new students because of new housing planned for the area.
BRE Properties will build 18 three- and four-story buildings on two sites in the Hacienda Business Park with just more than 500 rental units ranging in size from studio apartments to three-bedroom units, with most being two-bedroom apartments. About 15% will be subsidized units for low-income households.
A multi-story, high-density apartment project at the California Center -- formerly know as CarrAmerica -- would bring 305 studio and one-, two-, and three-bedroom apartments, with about four-dozen designated as "affordable."
And St. Anton Partners is expected to build a 168-unit, three- and four-story complex on West Las Positas Boulevard near Stoneridge Drive.
"Development is happening in the parts of town that we already have very large schools," said Deputy Superintendent Luz Cazares.
Projections by Davis Demographics and Planning indicate as many as 1,500 multi-family units and another 283 single-family homes are currently in the works, with the possibility of another 2,000 multi-family units and another 460 or so single-family homes in the future.
A 10th elementary in northern Pleasanton would be filled to capacity by 2018, according to the demographer's report, which says Fairlands, Donlon and Lydiksen could see a combined student population of 2,562 students by then -- an average of more than 850 per campus.
Future growth on the city's east side could mean an 11th elementary will be needed by the early 2020s, with projections from Davis Demographics showing the total elementary school population around 6,400 students by 2021.
The school board has only recently begun discussing new school sites, with no decision yet on a time-frame for building a 10th elementary.
The board is also early in its discussion about an 11th elementary. Davis Demographics presented seven scenarios for that school at a board meeting last month, and the board narrowed down its choices to three, all of which call for a 10th school in north Pleasanton and differing locations for the 11th school.
Board members are still weighing options that include moving the district offices to somewhere in the Hacienda Business Park and selling the land that currently houses district administrative offices, a maintenance facility, Village High School and an adjacent ball field.
They also want to consider new uses for property on Vineyard Avenue already owned by the district and known as the Neal School site, which could also involve a land swap.
The board has also floated the idea that the developers of homes in the East Pleasanton Specific Plan be asked to set aside land, and possibly build a school in the area.
"In looking at these documents, one thing that becomes abundantly clear is we're looking at adding two new schools," said boardmember Jeff Bowser at the January discussion of new schools. "Regardless of the cost, we have a duty to house those students appropriately."
2013 estimates put the cost of building a new school at about $37 million, not counting land acquisition and site preparations.
"There are various possible funding sources, and the board hasn't determined how it wants to do that yet," Cazares said. "Some possibilities are developer fees, some possible state dollars if they ever become available, and the third possibility is a general obligation bond."
"I think it's time for us to start talking about a bond," boardmember Joan Laursen said at the January discussion of new schools. "We have many, many projects that have not gone away."
Those projects include an estimated $92 million needed for immediate repairs to facilities, and other medium- and long-term needs that total nearly $400 million.
In 2012, a $260 million school bond was passed to pay for improvements at San Ramon Valley schools, including $29.6 million for the school in Dougherty Valley.
That measure -- the third bond in 14 years -- squeaked by with 55.19% in favor. The threshold to pass was 55%.
Local measures have not been as successful: two parcel tax measures have been defeated by narrow margins. In addition, some residents have been critical of the district's existing bond debt, which stood at nearly $65 million as of July 2013, according to the district's budget.