Voters in Alameda and San Francisco counties will have a chance on June 5 to approve tax measures funding ambitious child care programs that organizers say would provide enough subsidies for all low- and middle-income families who need them.

The two measures would each raise more than $140 million annually to expand existing child care programs, boost the educational quality of those programs and increase the pay of child care workers. The goal is to help parents go back to work after the birth of a child and improve children’s readiness for kindergarten.

“Child care is a huge expense for most families. Outside of housing, it’s often a family’s biggest expense,” said Margaret Brodkin, director of Funding the Next Generation, which pushes for subsidized child care initiatives statewide. “Some people think we can change the world for $25,000. Well, we can’t. Child care is expensive and we need these measures to make it happen for everyone.”

Alameda County’s measure would require a 2/3 majority to pass, but San Francisco’s only needs 50 percent plus one. That could change, however, depending on a potential legal challenge regarding how local tax measures are passed.

In Richmond, in Contra Costa County, voters will also be deciding on a youth measure on the June ballot. The measure isn’t expressly devoted to child care, but includes early childhood education amid a host of services for young people up to age 24. The services, which include after-school programs, job training and tutoring, would be funded by setting aside 3 percent of the city’s general fund.

Other child care initiatives are also in the works, as the August deadline for the November ballot approaches.

In Oakland, city leaders are aiming to put a new parcel tax on the November ballot that would fund preschool and other children’s programs for the city’s low-income families. If this and Measure A both pass, Oakland taxpayers would be funding both initiatives.

So far, all the proposals are in Northern California, but Funding the Next Generation is hosting a free conference in June in Los Angeles to spur counties in Southern California to launch their own measures.

If San Francisco’s Proposition C passes in June, the city would have some of the most wide-ranging subsidized youth services of any city in the country, Brodkin said. The city already subsidizes preschool for all 4-year-olds — funded through a 1991 charter amendment that sets aside 4 percent of property tax revenue for after-school programs, job training and other youth services — and has a limited program available for children as young as 3 months. Measure C would expand the child care and preschool programs so those programs can serve all low- and middle-income families who need it, said Supervisor Norman Yee, one of the measure’s sponsors.

Alameda County’s Measure A would be a half-cent sales tax. Like its San Francisco counterpart, the measure would pay to expand existing child care centers, recruit and train teachers, expand existing facilities and push for more home-based child care centers in order to meet the demand for new slots.

Although it would push the sales tax in some cities to nearly 10 percent, the investment is worth it, said Clarissa Doutherd, executive director of Parent Voices Oakland, a nonprofit that’s supporting the measure.

California’s average sales tax is 8.25 percent, although it’s 9.25 percent in most cities in Alameda County, including Oakland. Newark, Union City, Hayward, San Leandro and Albany have a rate of 9.75 percent.

Doutherd cited a study by James Heckman, a Nobel economist at the University of Chicago, who found that every dollar spent on early childhood education and high-quality child care saved $7 to $10 later on, as those children performed better in school, went on to higher-earning jobs, were less likely to be involved in crime and had fewer health problems.

“By prioritizing our youngest learners we can lift up an entire community,” Doutherd said. “It’s a high-cost investment but the return is great.”

Backers of both measures say they have strong public support, but historically child care initiatives have been a tough sell to voters. Last fall, all four child care measures on California ballots failed, in one case by just a few hundred votes. Voters in Marin, Napa, Solano and Sacramento counties all nixed child care initiatives. Marin, Napa and Solano all called for sales taxes, and Sacramento’s was a marijuana tax.

But organizers behind measures A and C learned from those campaigns, Brodkin said. Alameda County’s Measure A, for example, is backed by labor unions that support higher pay for child care workers, was composed after nearly 100 “listening sessions” with community members and has greater financial backing than its predecessors, Measure A campaign manager Casey Farmer said.

The measure is sorely needed in Alameda County, where housing costs rose nearly 12 percent last year, according to Zillow, and high-quality child care can be expensive and scarce, Farmer said. More than 7,000 low-income families in Alameda County are on the waiting list for subsidized child care and only 31 percent of young children with working parents are enrolled in licensed child care facilities, according to the Measure A campaign. In cases where parents can’t find care for their youngsters, they rely on neighbors, friends and family or are forced to cut back their work hours — a hardship for families already struggling to pay rent.

Oakland parent Delise Monroe was lucky to find subsidized child care for her sons, which has enabled her to work and support her family. Before, she had to rely on friends and relatives, who were often unavailable because they’re also working, or she quit jobs because she couldn’t find care for her children.

“We live in one of the most expensive places in the country,” she said. “I call it the Bay Area hustle. You need at least two jobs just to make it. And without child care, you just can’t do it. Child care is the piece of the puzzle you need to be independent … The kids have a safe place to go and for me, it’s opened a world of opportunities.”

Monroe now works three jobs, including one at the Oakland International Airport and another at Noah’s Bagels, and earns enough to support herself and her four children. Because she’s still low-income, however, she qualifies for subsidized child care.