Mayor Bloomberg’s plan to invest more than a billion new dollars in building and preserving housing across the city was welcomed with great fanfare in December, but his proposal is not just about newfound cash: He’s also called for making some sweeping changes to city housing policies that could generate affordable apartments for years to come.

The heart of the mayor’s “New Marketplace” plan shifts $500 million in federal money now used to maintain the shrinking stock of city-owned apartments, and leverages city bond funds to free up another $550 million, to create and preserve roughly 25,000 homes and apartments over the next five years.

This proposal won’t amount to nearly as much as Mayor Koch’s housing initiatives did 20 years ago: Bloomberg seeks to build 5,400 new units a year–about 1,700 of which will be affordable to families of four earning less than $37,680. In the early 1990s, as the $5.2 billion, 10-year Koch plan wound down, 7,800 new affordable units were built each year.

Nonetheless, says Joe Weisbord of Housing First!, “In the context of the city budget situation, it’s a major step forward.”

And though the budget for the mayor’s plan is modest, some of his ideas could generate more affordable apartments in some surprising ways:

• In the 1950s, city officials banned for-profit developers from building new single-room occupancy housing, because many SROs became crime-ridden hovels. Bloomberg proposes lifting the ban.

• The city housing authority owns hundreds of acres of vacant or underutilized land. The mayor hopes the city can build new affordable housing–perhaps for ownership–on that property.

• Neighborhood housing developers have long bemoaned that city agencies sell city-owned land with little public review. So the Bloomberg administration plans to shift oversight of all city property deals to Deputy Mayor Daniel Doctoroff, to “elevate housing development and neighborhood revitalization as priorities.”

How successful these–and other–new initiatives will be is anyone’s guess. “We have to be very watchful to see that the new resources are actually channeled, and that their use and distribution are fair and just,” says Community Service Society housing analyst Victor Bach. “But the mayor should be congratulated.”