San Ramon Valley kindergarten through third-grade classes, and ninth-grade English and math courses, may get a little bigger than some expected this coming school year, which begins Tuesday..

The San Ramon Valley school board voted 4-1 on Friday to change its participation in the state's class-size reduction program. During a separate meeting Tuesday, trustees discussed the decision amongst themselves and with members of the public who thought the May passage of a parcel tax ensured classes would stay small.

District officials say, besides saving money, larger class sizes will prevent hundreds of students — particularly in San Ramon's Dougherty Valley — from being diverted from neighborhood schools due of overcrowding.

The state program covers some costs for keeping such classes at a 20-students-per-teacher ratio. Schools get a decreased amount for slight increases above, and get nothing if they are too high.

The district had planned to increase class sizes, but after voters approved the San Ramon Valley schools Measure C parcel tax in May, and the governor's budget revision that reportedly accounted for a worst-case scenario, the district decided to keep the smaller classes.

However, district officials say the state budget agreed to after that doesn't include money for any classes added since the school year ended, which hurts the growing district, and that future budget projections are dismal.

Last week they decided to let those classes reach 22 students if needed. District officials expect them to gradually grow throughout the year. Of current kindergarten through third-grade classes, 57 percent have fewer than 20 students, 35 percent have 21 students each, and 8 percent have 22 students.

"We continue to face just a serious funding issue," said San Ramon Valley Superintendent Steven Enoch. "Just about every school district around here has increased class sizes."

The district, which has a $215 million budget for the 2009-2010 school year, could save $600,000 to $800,000 a year, said school district spokesman Terry Koehne.

Enoch said an added benefit of increasing class size is that it give the district more capacity at each site, which will keep about 300 students from being diverted from neighborhood schools.

Trustee Greg Marvel, who voted against the increase, said his main concern is that this has been decided too close to the start of school.

One parent reminded the board of a petition several hundred parents turned in after the parcel tax win asking for the class size reduction program be kept.

Trustee Board member Rachel Hurd said she supports classes being as small as possible, but isn't tied to the 20-to-1 ratio.

"It's a luxury we can't afford right now," she said.

San Ramon Valley Education Association officials understand the need for savings, said President Darren Day, but he said the union was not consulted beforehand.

Reach Eric Louie at 925-847-2123.