SAN JOSE -- Voters will soon decide whether to renew the city's library parcel tax, with city leaders already warning that letting the tax expire would prompt a big drop in library hours.

The San Jose City Council on Tuesday voted unanimously to place a measure on the June 3 ballot that, if approved by two-thirds of voters, would extend the library tax another 25 years.

The nearly $30-per-homeowner parcel tax, narrowly approved by voters in 2004, is set to expire next year. It funds nearly a quarter of the budget for San Jose's public libraries, which draw about 6 million visits per year.

City officials say extending the tax won't do anything immediately to restore library hours, which have been cut 13 percent in the last four years to help the city out of its budget hole. San Jose now spends less money on libraries per-capita than Oakland, and far less than San Francisco.

But losing the $8 million in annual funding the tax provides would likely result in the city laying off about 50 librarians, slowing down new book and material purchases and even shutting down some of the system's 23 branches.

Library director Jill Bourne said the unemployed or those without computers rely on the library, while letting the measure lapse could even result in kids "not being able to come to story time -- imagine that."

"We're not where we want to be, but we certainly don't want to go in the other direction and close libraries," Councilwoman Rose Herrera said.

Like all city taxes dedicated toward a special use, the measure will require a two-thirds approval by voters, giving supporters little room for error. A poll last month showed 57 percent of likely San Jose voters would definitely approve the measure, but when pushed, a total of 84 percent of voters said they were at least leaning toward voting for it.

During the presidential election in November 2004, the original library measure passed with 67.2 percent of the vote -- a margin of less than 1,400 votes. The turnout is likely to be much smaller for the June primary. But measures to extend existing taxes typically fare better than proposals to raise taxes.

This time around, in approving $505,000 in funds to place the measure on the ballot, council members were confident that there would be no significant organized opposition given the popularity of libraries. Meanwhile, a coalition of supporters led by ex-library director Jane Light and recently-retired city manager Deb Figone, with a team from the Library Foundation and the Friends of the Library, is working to raise money to run a campaign to pass the measure.

Not as many people use the library anymore, however. Since the recession-era cuts began, the number of visits and items checked out at San Jose libraries has dropped about 30 percent. A recent city survey found 61 percent of residents said they went to a library once, twice or never in the past year.

The library tax has increased from $25 per single-family house 10 years ago to $29.84 today -- or 0.04 percent of the median household family income. If approved, it would continue to increase at the rate of inflation for the next quarter-century.

Contact Mike Rosenberg at 408-920-5705. Follow him at twitter.com/RosenbergMerc.