The Miami City Commission tentatively approved a measure last week that would change the minimum square footage required for condo and apartment units.

Current regulations mandate that they must have at least 400 SF of living space. The new law would reduce that number to 275 SF in certain situations. A final vote on the matter is scheduled for Dec. 14.

The Daily Business Review reports that the new rule would require each unit to have a full bathroom and kitchen. There would be no requirement for developers to incorporate parking spaces; in fact, parking would be maxed at one spot per unit.

For properties zoned for more than 150 units per acre, microunit developments would be limited to transit-oriented areas, according to The Real Deal, such as near Metrorail and Metromover stations. Microunit projects could not be built next to low-density residential areas.

Metro1 developer Tony Cho, who is already developing two towers in Wynwood with units as small as 419 SF, hinted at building microunits near the Underline, a park/urban trail in development underneath the Metrorail, with its northern end in Brickell.

“Miami is evolving at a fast pace and there is a widespread desire for walkable neighborhoods with access to public transit and quality housing attainable for a diverse group of people,” Cho said in a statement. "This legislation will allow us to create the type of high-quality, amenity-rich lifestyle that’s in such high demand, and just steps from the Underline."

A rep for Cho said that he was not ready to divulge details. Cho and Robert Finvarb in January paid $18M for a site near Brickell City Centre and had announced plans for a mixed-use hotel there. They played up its closeness to the Underline.

Other developers have floated plans to develop microcondos in the MiMo district.

By zoning for smaller units, Miami is following the lead of other cities. New York has a 400 SF requirement but has recently experimented with waiving that. San Francisco and Washington, D.C., permit units at 220 SF.

Microunits have gained popularity in recent years. Developers like the idea of fitting more sellable or rentable units into a space, and urban planners have suggested that the smaller, cheaper units — although often more expensive per square foot — could help alleviate the affordable housing crisis in many areas.

But there has also been a backlash. Some critics say microunits are frequently built with shoddy construction or that they are sometimes too dense, creating traffic problems.

One urban planner warned against creating “modern-day tenements” and worried that microunits, if poorly planned, could reverse the trend of people moving back to urban cores.

In West Palm Beach, developer Jeff Greene recently backed out of a plan to build microunits. A similar project in Tampa was also scrapped this month. And other developers said at a recent Bisnow event that they were not profitable after factoring in the cost of kitchens, bathrooms and appliances for each small unit.