There’s another story in Sunday’s Washington Post about immigrants living six to a room in the suburbs.

“There were six makeshift kitchens,” said Vince Diem, an inspector in Herndon’s Department of Community Development. Extensive interior alterations had been carried out — all without permits — to subdivide the residence so that other families and single adults could live there. The living room, for example, had been converted into a kitchen and bedroom occupied by one family.

“I would say it was a hazardous situation,” said Diem, who counted 10 people living in the townhouse. The owner, an Egyptian woman who was sharing the home with her teenage son and eight Middle Eastern people unrelated to her, professed ignorance of local ordinances against “excessive occupancy” and unauthorized construction, Diem said.

Another recent investigation found 16 people from Latin America living in a single-family home that also had undergone extensive interior construction work without permits, he said.

Unless you’re living in a police state, the density of a town isn’t really determined by zoning. It’s determined by the price of the housing, the income levels, the transportation options, and the job opportunities. Where you’ve got a lot of jobs that pay little money combined with poor transportation options and relatively expensive housing, you’re going to have low-wage people sharing housing with enough other low-wage people that they can afford to live there. Herndon has a lot of low-wage jobs, basically no transportation options that don’t involve buying a car, and fairly expensive housing.

Planners can prevent density by simply ensuring that the economy of an area won’t ever generate the kind of opportunities that spur people to live six to a room; but we’ll assume that, except for pure tract-house developments, some kind of economic vitality is desirable.

Assuming they don’t kill off the economy, and thus density, entirely, the only thing that planners can really control is whether density is going to be contained in structures designed for it, or whether it’s going to be contained in impromptu boardinghouses. Refuse to allow people to build the kind of housing that’s actually in demand, and you will have problems. And by ‘the kind of housing that’s actually in demand’, I mean, of course, inexpensive housing, housing that people without much money can actually afford without heavy subsidies. Note that this is something quite different from what’s called affordable housing.

Local authorities don’t like to do this, though; they prefer to zone land in such a way that only millionaires with no kids are encouraged to move in, occupying (and paying taxes on) a lot of land while consuming little in the way of services. Poor people, living in small apartments, paying little tax and consuming lots of subsidized services, are precisely, and somewhat justifiably, what a town doesn’t want.

The problem is, zoning poor housing out of existence doesn’t mean that you won’t have poor people consuming your services, as the Post story illustrates. It just means you’ll have poor people consuming your services while living in unsafe conditions in chopped-up middle-class housing.

You cannot outlaw poverty, but only the outward appearance of poverty. And it seems that when you outlaw the outward appearance of poverty, the poverty you find when you scratch the surface is much more squalid.