New York Citys aggressive efforts to create affordable housing have rightfully won praise from housing experts nationwide. But less widely recognized is the extent to which informal dwellings, illegal and unregulated, have proliferated in response to the citys surging housing demand. During the past fifteen years informal housing may have accounted for as much as half of the citys net housing creation, approaching a scale comparable to the celebrated Mitchell-Lama program.

In many communities, illegal housing units have reached a critical mass, eroding neighborhood aesthetics, straining services, and turning parking into a frustrating ordeal. Many feel the situation is hopeless, with demand for housing simply overwhelming the citys capacity to enforce housing and zoning codes. Cynics wonder if there isnt a dont ask, dont tell attitude towards enforcement, with inaction on the part of local officials encouraged by fear of what vigorous enforcement would uncover. In the meantime, an illegal market thrives, and unplanned, unanticipated density crowds neighborhoods once considered among the citys finest.