Standard & Poor's warned Monday that school districts across the country could see their credit ratings drop because of state budget problems.

The warning comes a week after the major bond analysis firm affirmed the Livermore school district's relatively solid credit rating, but revised the rating's outlook to "negative."

A lowered credit rating can mean paying more interest on new debts.

"For those school districts in California, it's not looking very good," said Christopher Mortell, a spokesman for Standard & Poor's. Analysts at the firm said it's hard to say how much the costs would rise, as it depends on market conditions and individual lenders.

Education funding in most states, including California, has been somewhat spared from cuts compared to other programs, according to the report. Ratings have been stable, though as states have had to cut education spending since the downturn that began in 2001.

The report showed that the number of districts that face downgraded credit ratings has grown.

The firm said that nine California school districts have negative credit-rating outlooks, with most of those determinations made in the last couple of years. The firm gives each district either a positive, stable or negative outlook. No California districts have a positive outlook.

In the Bay Area, there are only three schools with a negative outlook -- Livermore, Benicia and Berkeley. The Berkeley district drew its negative outlook in May and Benicia received its rating in July, said Markela Soward, a Standard & Poor's analyst.

Last week Standard & Poor's revised the Livermore district's outlook to negative, though its credit rating remained unchanged as A+. The firm has 11 rating levels -- AAA is the highest -- with pluses and minuses within that for smaller variations.

The firm describes the A rating, its third highest, as meaning the agency has a "strong capacity to meet its financial commitments but is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligors in higher-rated categories."

Most California school districts have an A rating, Soward said.

She said the outlook was revised because there is a possibility Livermore may not meet its financial obligations over the next three years. The Alameda County Office of Education assigned the district a fiscal adviser after Livermore's current budget failed to meet state reserve requirements.

Susan Kinder, the district's finance director, said the district still has about $57 million in bonds to issue as part of 1999's Measure L, a bond measure that allowed for borrowing up to $150 million for projects benefiting the district, city and Livermore's park district. She said new school bonds won't be issued for a few years because the district is still building with money from past bonds. The district is paying 4.75 percent interest on bonds issued in 2002.

Livermore Deputy Superintendent Bob Bronzan was happy with the Standard & Poor's review, which Soward said was part of the firm's normally scheduled update. Bronzan said keeping the current credit status, at a time when other districts may be losing theirs, shows the district is on its way to recovery.