(CNN) - It's too close to call in California's Senate and gubernatorial battles, according to a new poll.
A CNN/Time/Opinion Research Corporation survey released Wednesday indicates that Sen. Barbara Boxer holds a 48 percent to 44 percent margin over her Republican challenger, Carly Fiorina, but Boxer's 4-point advantage is within the poll's sampling error. Five percent of people questioned say if the general election were held today they'd vote for neither candidate and three percent were undecided.
"In a battle between two women, female voters will be a key constituency. Right now, 48 percent of women would pick Boxer compared to 43 percent for Fiorina. Six years ago, Boxer won 65 percent of the women's vote," says CNN Polling Director Keating Holland.
"The suburban vote has always been important in California, and it looks like that's the home of the California swing voter this year as well," adds Holland. "Boxer piles up a 19-point lead in urban areas and Fiorina has a 27-point advantage in rural California. Among suburban voters, the two are running fairly evenly, with 48 percent of the suburbs currently saying they would choose Fiorina and 44 percent picking Boxer."
According to the poll, Whitman has a two-point advantage over Brown, 48 to 46 percent. Whitman's two point margin is well within survey's sampling error.
"Both candidates come from the Bay Area - Oakland for Brown and the Silicon Valley for Whitman," says Holland. "But Brown is the one with the home field advantage in the Bay Area. He has a 51 percent to 43 percent margin among Bay Area voters. Whitman has a similar edge among voters in Southern California and the Central Valley."
The survey indicates that Whitman holds a five point margin over Brown among independents.
"The gender gap means that women usually vote Democratic, but female voters are evenly divided between Brown and Whitman. That may be due to some women choosing a female candidate over a male, depriving Brown of the traditional level of support from that key group," adds Holland.
Whitman is the billionaire former CEO of Ebay. She's spent more than $110 million of her own money on her campaign. Brown, who served as California governor for two terms in the 1970's and 1980's, is currently the state's attorney general.
The winner of November's general election will succeed term-limited Republican Gov. Arnold Schwarzenegger.
The CNN/Time/Opinion Research Corporation poll was conducted September 2-7, with 866 registered voters in California conducted September 2-7. The survey's overall sampling error is plus or minus 3.5 percentage points.
– CNN Deputy Political Director Paul Steinhauser contributed to this story