District taxpayers currently pay an annual $493-per-parcel, generating $9.4 million a year, about 6 percent of the school district's operating budget.
Measure A is a $589-per-parcel tax that would yield about $11.2 million a year for the district's approximately $154 million operating budget.
The parcel tax would expire in six years and would carry an optional exemption for seniors as well as a 2 percent annual "escalation adjustment." A two-thirds majority is required for the measure to pass.
The Palo Alto Board of Education chose a mail-in ballot rather than an in-person election when it unanimously voted to submit the tax to voters, saying it would save money.
Voters in the Palo Alto Unified School District, which includes Palo Alto, Stanford University and parts of Los Altos Hills, should receive ballots in the mail Monday.
Ballots must be mailed back no later than April 30 to ensure they are received by the Santa Clara County Registrar of Voters by the May 4 deadline, Measure A backers said.
Ballots also may be dropped off at Palo Alto City Hall, 250 Hamilton Ave.
A parent-led campaign committee, "Support Palo Alto Schools 2010," has been holding weeknight phone banks to identify supporters.
No organized opposition has surfaced in the Measure A campaign.
Pro-Measure A volunteers will begin calling supporters next week to make sure they have returned their ballots, campaigners said.
Measure A backers plan to rally at Lytton Plaza Saturday from 11 a.m. to 1 p.m.
Featured speakers will include State Sen. Joe Simitian, D-Palo Alto, a Paly graduate and former member of the Palo Alto school board; Stanford University football coach and Paly graduate Jim Harbaugh; Palo Alto Mayor Pat Burt; Palo Alto City Council Member Yiaway Yeh, a Gunn High School graduate, and Stanford Freshman Dean Julie Lythcott-Haims.
School board President Barbara Sih Klausner and Gunn Student School Board Representative Steve Zhou also will attend.
"This community has long supported and benefited from its fine school system," said campaign co-chair Anna Thayer, a mother of four and vice-president of the PTA Council Executive Board.