In the final weeks before the Nov. 5 election, a measure that would double the county’s quarter-percent homeless sales tax was closing in on the majority it needs to pass, a new poll of likely Los Angeles County voters found.

Half of those surveyed said they would vote for Measure A, or already had done so, in the poll taken by the UC Berkeley Institute of Governmental Studies and co-sponsored by The Times.

That was a gain of one percentage point over the previous IGS poll in September and three percentage points above its August poll. Thirty-four percent said they would vote no, or already had, up from 33% in September but down from 36% in August. Sixteen percent remained undecided, did not vote either way on the measure or could not recall how they voted.

“These numbers are very stable,” said Mark DiCamillo, director of the Berkeley IGS Poll. “It’s close.”

The survey, conducted Oct. 22 to 29, had a margin of error of plus or minus three percentage points, making it impossible to say whether the 50% support means the measure is winning or losing.

But the upward trend was a good sign for the Measure A campaign, DiCamillo said. “It’s not trending against them.”

Another positive came from the responses of the nearly 26% of respondents who had already voted. They favored Measure A by 54% to 31%, compared with 49% to 35% for those who had not yet voted.

“They’re the likeliest of likely voters,” DiCamillo said. “If you’re on the yes side, that would be the group you would want to have in the bank.”

However, DiCamillo noted those results could be skewed by the historical preference of Republicans to vote in person. Support for Measure A among Republicans was only 19% while 65% of Democrats supported it.

If it passes, Measure A will repeal Measure H, a quarter-percent sales tax approved by voters in 2017 to fund homeless services, and replace it with a half-percent sales tax expected to generate more than $1 billion annually. If not replaced, the Measure H tax would expire in 2027. The new tax, if adopted, would remain in effect unless repealed by voters.

The new measure would expand the reach of the current one by earmarking nearly 40% of the funds to homelessness prevention and affordable housing. Sixty percent would go toward comprehensive homelessness services, essentially replacing the existing revenue from Measure H. Some of that would be eaten up by increases in the reimbursement rate for interim housing proposed to go into effect next year. About $175 million, or 26% of the Measure H budget, goes to programs that would have increases of between 50% and 100% by July.

Opponents, including the Howard Jarvis Taxpayers Assn., object to the measure having no sunset date and argue that it is a new tax put on the ballot by “so-called ‘experts’ who have already received hundreds of millions of dollars for homeless programs while the problem got worse” and will “get the contracts to operate the same failed homelessness programs.”

They also object to what they called a “court-created loophole” that makes the measure easier to pass.

A coalition of nonprofit organizations including United Way of Greater Los Angeles and the California Community Foundation qualified the measure for the ballot. Because it’s a citizen initiative, under a 2020 decision by the 5th Appellate Court, it is exempt from the two-thirds majority required of government-initiated taxes and can win with a simple majority.

Backers raised about $4 million both to gather signatures and for a media campaign. The California Community Foundation, which contributed $2.1 million to the campaign, has also invested another $4 million in a community organizing drive to generate support, said the organization’s president and chief executive, Miguel Santana.

The campaign was finishing with an aggressive telephone drive to inform voters of what Measure H had accomplished, said Tommy Newman, United Way vice president for public affairs.

“We’ve talked to more than 100,000 voters on the phone,” Newman said. “This is the time voters make their decisions.”

Newman said the campaign’s polling shows an increase in support when voters learn more about the measure. The No. 1 argument is that homelessness would go up 28% if H expires, a projection made in a report by the Los Angeles County chief executive.

“Your average voter isn’t quite sure what progress has or hasn’t happened,” Newman said. “Learning that there are tens of thousands of people who are receiving housing and services now and that money would go away is the first time many voters realize what has happened with the previous work.”