Both candidates for governor agree that the cost of housing in California, to rent and own, is too dang high. They concur that the skyrocketing homeless population is a travesty. And they want to help the 1 in 5 Californians who lives in poverty.

But that’s pretty much all they agree on when it comes to how to make California more affordable.

Gavin Newsom, as has been his wont during two decades in public office, is a man with a plan. Fifteen of them, the Democrat says, that will address California’s housing and homelessness problems.

John Cox, as has been his wont during his two decades of trying to be elected to office, is a man with a critique. The GOP candidate says “all of these plans don’t mean a thing if we can’t change a lot of these laws that that are driving housing costs through the roof.” As for specifics on how he’d do that, Cox said, “We’ll talk about that after I’m elected governor.”

Until then, here are some areas where the candidates are trying to address California’s affordability problems:

Housing: Both candidates propose building their way out of the housing shortage. It’s easier said than done.

Newsom aims to build 500,000 new homes a year until 2025, a goal he concedes is “audacious” — probably because California has built more than 300,000 homes in a year only twice in the past six decades, according to the Construction Industry Research Board.

Newsom offers several carrot-and-stick ideas on how to get there.

One carrot: California now offers $85 million annually in tax credits for developers to spur the construction of affordable housing. Newsom proposes increasing the state’s share to $500 million, which he estimates would “generate an additional investment of $1.5 billion to $2 billion in new affordable housing production.”

The stick: He’d work with regional agencies to withhold transportation funding to cities that don’t build the number of units they commit to in their state-required housing plans.

Cox wants to build 3 million units over the next decade. The focal point of his housing program revolves around reforming the California Environmental Quality Act, colloquially known as CEQA. He said eliminating many of the law’s provisions and “government red tape” would speed production of housing.

Homelessness: Cox said that as mayor of San Francisco, Newsom “didn’t solve the homeless problem here at all. And it’s gotten worse” — a statement that the nonpartisan PolitiFact found to be “half right.” The homeless population on the street dropped 31 percent during Newsom’s tenure, but the overall number of people without full-time shelter increased by a little more than 1,000, according to PolitiFact.

Cox proposes quadrupling the renters tax credit to help people preserve their housing. But he offers few ideas on how he’d get people off the streets beyond broad statements about how California should enter into more public-private partnerships with nonprofit organizations. He would fund these programs by ending construction on what he calls “boondoggles” like “the train to nowhere” — California’s $77 billion high-speed rail project.

Newsom offers several ideas on how to reduce homelessness, most of which involve offering incentives, instead of a direct handout, to developers and cities to build housing. He proposes offering block grants to counties for homeless programs, so they can tailor help to what’s best for their population. He would offer tax credits to landlords who rent space to homeless people, to developers who build permanent supportive housing, and to employers who hire homeless people.

Rent control and other state ballot measures: Both candidates oppose Proposition 10, which would repeal a state law that restricts cities’ ability to impose rent control, which critics say would discourage housing construction.

Both support Proposition 1, a $4 billion bond measure that includes $3 billion for construction and preservation of affordable rental housing and $1 billion for loans for veterans to buy homes and farms. Both support Proposition 2, which would enable the state to spend $2 billion from a 2004 mental health bond measure on housing for homeless people.

Cox supports Proposition 5, which would let homeowners 55 and older and all disabled homeowners move anywhere in California and keep their Proposition 13-level property taxes. Proponents say it would free up housing in high-demand areas. Critics say it would hurt local budgets and benefit mainly wealthy people. Newsom opposes the initiative.

What about taxes? Both Newsom and Cox say they’re dissatisfied with California’s tax structure, which relies heavily on revenue from income taxes that keep the state flush during good times, but dry up when the economy turns south. But they differ on whether one solution is to change Proposition 13, the 1978 ballot measure that capped property taxes, so that more of the burden falls on businesses and less on homeowners.

Cox, who wants to cut income taxes, would leave Prop. 13 alone. Cox does say he would create a commission to come up with a “revenue-neutral” plan to reform the state’s tax structure.

Newsom said that “everything would be on the table,” including Prop. 13. He would like to broaden the tax burden, saying 85 percent of California’s economy is not taxed. He points out that many states include taxes on services that California doesn’t. Like Cox, he would convene a group to recommend changes to the system.

Gas tax: Cox has been a leading supporter of Proposition 6, which would repeal the $52 billion increase in gas taxes and vehicle license fees that is earmarked for road and transportation upgrades. He says the tax disproportionately hits working-class Californians who have to drive long distances to work — because they can’t afford to live near their jobs.

Newsom supports the tax, saying it’s the best way to fix worst-in-the-nation roads, and points out that Cox hasn’t identified how he’d pay for upgrades other than promising audits to root out “waste and abuse” in state government.

Joe Garofoli is The San Francisco Chronicle’s senior political writer. Email: jgarofoli@sfchronicle.com Twitter: @joegarofoli