Palo Alto voters could see a new school bond measure on the November ballot if the Board of Education decides to seek one to fund the next 20 years of facilities improvements in the district.

Trustees discussed Tuesday the potential of a $480 million or $375 million bond that would replace a $378 million bond voters approved in 2008. No trustee expressed opposition to the new bond.

The district is in the thick of developing a 20-year facilities master plan that would guide the bond measure, if approved. A district team and architecture firms have since last summer been gathering input from principals, staff and others about the upgrades they would like to see at their schools. The total cost of the schools' wish lists and other possible upgrades, presented to the board on Tuesday, is $1.18 billion.

The current bond has funded significant improvements across the district over the last decade, from new classrooms at the elementary and middle schools to Palo Alto High School's Performing Arts Center and Media Arts Center and Gunn High School's aquatic center and Central Building Project, but the schools say more is still needed to keep the campuses up to standard over the next 20 years.

At the elementary level, every school except Nixon Elementary School has asked for a new multipurpose room, which have been described as aging and unable to handle school capacity. New learning centers, resource centers, larger kindergarten classrooms, air-conditioning, accessible playgrounds and expanded administrative buildings have also been proposed for the elementary schools.

The middle schools are looking to modernize their science labs, add more administrative space to improve supervision and make room for new wellness centers and add gender-neutral bathroom facilities. Jordan and JLS middle schools have also proposed building new libraries.

Gunn High School, where the new two-story Central Building is currently under construction, is hoping to renovate its administrative and student services buildings, build a new two-story arts building, add two science labs and fully modernize Spangenberg Theatre, among other proposed improvements.

With a new bond, Palo Alto High School could see the renovation of the Tower Building and Haymarket Theatre, which was promised in the current bond but did not come to fruition. The site's wish list also includes tearing down two existing classrooms building to house a new wellness center, dining facility and more flexible, multiuse career technical education (CTE) labs.

"Nothing here seems like a boondoggle," board member Melissa Baten Caswell said of the proposed projects.

The estimated cost for the elementary school upgrades is $352 million; the middle schools', $216 million; and the high schools', $258 million.

Board members asked district staff to also consider future enrollment growth in their plans. Bond Program Manager Bob Golton said it's difficult to accurately predict growth — "our crystal ball is very cloudy as it relates to five years from now, 10 years from now, 20 years from now," he said — and it's up to future boards to take action, if necessary, to reprioritize the bond projects.

The future use of Cubberley Community Center, the 35-acre campus that the district owns with the city, still hangs in the balance as a master planning process moves forward.

An opinion poll conducted by an outside firm indicates there is sufficient support for a new bond. Firm TBWB Strategies polled 400 likely voters in March and April. One in four of them currently have children in the district.

After hearing both arguments for and against the bond, 63 percent of voters polled said they would vote for the more expensive measure — above the 55 percent threshold required for bonds.

The opposition arguments — including recent changes to federal tax law and concerns about district's leadership handling of the budget and student sexual violence — didn't appear to be problematic, said Gene Bregman of TBWB Strategies, who conducted the poll. Less than 25 percent of those polled rated the anti-bond arguments as reasons they wouldn't support the measure.

Public perception of the district does seem to be suffering somewhat: 63 percent of voters polled rated the district as doing an excellent or good job, down from 78 percent in 2014.

Community member Robert Smith told the board that he thinks the bond is "poorly timed" and that school leadership must first show that the boat has been righted after several years of upheaval, including failures to adhere to federal civil rights law Title IX, financial mismanagement, the divisive renaming of Jordan and Terman middle schools and high turnover at the district office.

"I am second to none in my disappointment in the district for some of the management and financial missteps we've had the last few months and couple years," agreed board member Todd Collins, but, he added, "the benefit for the students from continuing our building program and continuing it in a steady and predictable way is very, very high."

Staff will ask the board at its May 8 meeting for authorization to further refine the proposed project list and develop a bond resolution, which would need to be approved before an Aug. 10 deadline to place the measure on the November ballot.