GEOFF BENNETT: The cost of housing is a top financial concern for voters this election year, second only to inflation.

That's according to a Gallup poll this month.

It comes as home prices in the U.S. jumped 6.5 percent in March compared to a year earlier, making it the sixth time over the past year that home price indexes hit a new record high, all of this as interest rates remain at their highest levels in more than two decades.

I spoke earlier with Alex Horowitz.

He's project director of the Housing Policy Initiative at The Pew Charitable Trusts.

Alex Horowitz, thanks so much for being with us.

ALEX HOROWITZ, Housing Policy Initiative Project Director, The Pew Charitable Trusts: Hey.

Glad to be here.

GEOFF BENNETT: So one indicator of just how tough this housing market is, the number of first-time homebuyers who are relying on their parents to co-sign loans or to help with down payments, it's as high as it's been in at least 30 years.

That's according to a Freddie Mac analysis of loan applications.

What are the implications?

ALEX HOROWITZ: So, right now, home prices are about the highest they have been as a share of income.

And with interest rates being this high and a structural shortage of housing, housing affordability has gotten awfully tough.

And it is very tough to crack into this market as a first-time homebuyer.

GEOFF BENNETT: And it strikes me it also widens the divide between those who can afford a home and those who can't.

ALEX HOROWITZ: So, we see that people who are previously homeowners have equity in that home.

And so it's much easier to trade up to another home, because the value of the home they're in has been increasing as well.

But if somebody hasn't been in the market before, then it's tough to break in, and rents are also at an all-time high as a share of income.

So saving up for a down payment has gotten the hardest that it's ever been because residents are spending so much on rent while they're waiting to buy.

GEOFF BENNETT: The U.S. is in a long-term housing shortage right now, with the construction of new homes failing to meet the demand.

They also have people who locked in record low interest rates during the pandemic who are reluctant to move, for obvious reasons, all told, a shortage of some seven million homes.

What does a viable policy solution look like?

ALEX HOROWITZ: So there are places in the U.S. that have succeeded in adding to their housing supply, even while home construction in the U.S. is awfully low and not keeping up with population growth and the need for more housing.

And the places that have been successful have made it easier to build.

That's true in cities, it's true in towns, and it's true in states.

And in those places that have added a lot of supply by updating their zoning, by allowing townhouses, duplexes, apartments, we see real results.

Affordability is improving in places like Minneapolis.

It's improving in places like Houston, even while it's getting worse in most of the U.S. GEOFF BENNETT: What about California?

Because California lifted restrictions to encourage more multifamily housing and alleviate the state's housing shortage.

But two years after that law went into effect, according to state data, as reported by The Wall Street Journal, the number of housing units completed is in the dozens.

What went wrong in California?

ALEX HOROWITZ: That California duplex law hasn't worked yet, and it often takes more than one try to get a state law right.

California enabled duplexes.

They're technically allowed, but they left jurisdictions lots of ways to block them.

And, again, we're talking about at this point individual homeowners looking at duplexes.

And so it doesn't add enough to the housing supply only to allow duplexes.

That's not a viable solution, but really it's local regulatory barriers to those duplexes that haven't been fixed in the state law.

When California first legalized accessory dwelling units -- so that's a basement apartment, a backyard apartment, a garage conversion -- they didn't get many.

And it took until 2017, after they started trying in the '80s, until they started getting serious building of accessory dwelling units.

Now more than 100,000 of those have come online in California, but they needed a very strong state law in order to produce them.

GEOFF BENNETT: So those states and cities that have seen success in encouraging more supply and density of housing, what are they doing?

ALEX HOROWITZ: The foremost tactic that has worked has been to make it easy to build apartments near commerce or near transit, because builders are ready to build apartment buildings.

They know how.

The main obstacle is that the permitting is very difficult because most land doesn't allow apartment buildings because of local regulatory barriers.

But we see that the cities that have made the most progress in improving affordability have said yes to apartment buildings.

They have said yes to it as a matter of right in their zoning, so that builders know, if they submit an application to build an apartment building, they're going to be able to do so.

And now we're seeing states start to model their laws on the success of those localities, with five states now making it easier to build apartments on land that zone commercial.

And that has a lot of potential to add to the housing supply, even though all of those state laws are very recent.

So we haven't seen them have a big effect yet.

GEOFF BENNETT: Alex Horowitz is the project director of the Housing Policy Initiative at The Pew Charitable Trusts.

Thanks so much for being with us.

ALEX HOROWITZ: Thanks a lot.