This morning I was on the Brian Lehrer show talking about the Obama Administration’s conference on the future of housing finance. You can listen to the interview here.

One thing that came up during the interview was this concept of renting. Strange as it may seem, renting is a key part of the housing market. Indeed, tens of millions of American families rent. And as the homeownership rate drops each quarter, chatter is growing louder about how renting might be a decent option—not just a fall-back plan—for plenty of people. (This vision of a renting renaissance often goes hand-in-hand with an important demographic shift; aging Baby Boomers are less likely to want to live in 4-bedroom houses with quarter-acre lawns to mow.)

There’s just one big problem: the reality of our built environment.

According to government data, 89% of single-family detached houses are owner-occupied. Meanwhile, 83% of apartments are rented. There is a certain logic to this. An apartment building provides an economy of scale for a landlord that a suburban housing development doesn’t.

But what that means is, if we as a nation start saying that renting is a fine and legitimate choice—which, incidentally, would be the first time we did so since Herbert Hoover became Commerce Secretary in 1921—then we’d also implicitly be saying that more people are going to live in apartments.

Would America be okay with that? I’m not really sure. I was talking about this the other day with Harvard economist Ed Glaeser, and he said that town houses provide the best shot at renting catching on as a fashionable choice. You aren’t locked into a huge mortgage or floor plan, but you still get a little green space out back and a place to park your car. About half of attached single-family dwellings are rentals.

But there’s another problem Glaeser brought up: local land-use regulations. He pointed to this paper which finds that 18% of the municipalities within 50 miles of Boston don’t allow any multi-family housing to be built. Another 44% allow such construction on less than 10% of available land. In other words, the choice to rent not only implies living in an apartment, but it also heavily restricts what neighborhoods are available to you. At least in eastern Massachusetts. Although it’s hard to believe that’s the only place you find NIMBYs.

The overarching point is that a lot comes along with the transition from owning to renting. It doesn’t necessarily make sense that so much should depend on whether you send a check each month to a bank or to a landlord. We need to keep in mind, though, that much in fact does.