Living down under

As New York necks crane skyward in search of solutions to a chronic shortage of affordable housing, the city overlooks a resource literally at our feet: home basements by the tens of thousands, with the potential to be made habitable at low cost if only government bureaucracies help make it so.

Citizens Housing and Planning Council scoured every lot in the five boroughs and found that as many as 38,000 basements of single-family houses could be ready to roll as rental apartments — sufficiently above street level and shielded from flooding to provide safe and comfy homes, a boon not just for future tenants but for owners upstairs who need a hand paying the mortgage.

Of course, plenty of homeowners already do just that — too often illegally, without proper building permits, exposing people and property to fire and other hazards.

Too often also, neighbors tell local elected officials that they resent cramming more apartments into dwellings, and cars into scarce parking spots.

Bringing the real estate underground housing into broad daylight — with expedited building permits and financial assistance for homeowners ready to make the leap to legitimacy — will take a level of commitment and courage that Mayor de Blasio hasn’t yet reached.

Evaluation of “informal dwelling units” merited mention in the mayor’s housing plan nearly three years ago, and a task force now ponders a test run in East New York, Brooklyn, but not a peep so far from the mayor himself.

De Blasio now has the facts of the potential at hand. He also has the example of Toronto, where a two-decade-old program has unleashed 75,000 basements and other spare spaces as dwellings.

That’s nothing to look down upon.