"The idea behind this was to just provide another tool in everyone's toolkit to improve the amount of housing that could be built, particularly affordable housing, because it allows you to 'trade' some of your numbers," said Councilwoman Pat Showalter, who served on the committee proposing the idea.

The latest RHNA -- short for Regional Housing Needs Allocation -- states that Santa Clara County needs to generate just over 58,000 housing units between 2015 and 2023 to keep pace with projected growth. Under the current framework, each city is given a share of that number through a complex algorithm. It's an uphill battle for cities trying to contest the allocation. Creating a subregion would mean more flexibility for cities to essentially trade their housing obligations, with the ultimate goal of creating more housing across the county.

Over the last two years, members of the Cities Association of Santa Clara County have been considering what's called a "RHNA subregion," which would empower local elected officials to alter how much housing each city is asked to build in order to keep up with job and population growth. Mountain View City Council members voted 5-1 in favor of the idea Tuesday night, with Mayor Lenny Siegel opposed and John McAlister absent.

In the latest move to increase housing growth in the region, city leaders throughout Santa Clara County are looking at a new strategy, opening the door to cross-city housing development and the ability to "trade" the obligation to build new homes in exchange for money and resources.

So could a neighboring city like Los Altos or Palo Alto 'dump' its housing growth into Mountain View? Technically it could happen, but Prevetti said she doubts Mountain View's council members would agree to the deal, regardless of how many resources would come with it.

That's unlikely to happen, argued Los Gatos Town Manager Laurel Prevetti, who serves an administrative role on the cities association subregion task force. Under the current vision for the subregion, each city would have an elected official representing its interests, along with a representative from the Santa Clara County Board of Supervisors who could weigh in on all major decisions. Prevetti said the ground rules would be that no city would have to unwillingly accept a higher allocation of housing.

"All I can see coming out of this is other cities trying to get Mountain View to build housing that they're obligated to build," he said.

It could also lead to cities opposed to housing growth shirking their responsibility to build housing, particularly in jurisdictions with a groundswell of opposition to development. Mayor Siegel said he was skeptical of the idea, which he said looks like a time sink that would lead to neighboring cities pushing their responsibility for housing growth onto Mountain View.

The idea has received a warm reception from 11 cities in the county -- Mountain View now included -- while the cities of Milpitas, Palo Alto and Sunnyvale have yet to officially weigh in. On paper, the subregion could mean better cross-city planning along transit corridors or near employment centers, bigger housing developments that take advantage of economies of scale and a greater ability to put housing near existing services.

"Some (cities) have money, and they would be willing to spend and get the political will to contribute money to build what they can't get built locally," she said.

Although the purported goal of the subregion would be to help cities meet regional housing needs, Mountain View doesn't need any help. The city is on track to exceed its housing needs allocation and is expected to outperform other Santa Clara County cities in establishing more deed-restricted affordable housing as well. Showalter told the Voice that creating a subregion would likely give greater benefits to low-growth cities in the area seeking to fulfill their housing allocation through alternate means.

"The deal-breaker jurisdiction is the county," she said. "If all 15 cities say, 'yeah, we want to do this,' but Santa Clara County doesn't, then that's the deal killer."

The goal is to get city councils across all 15 cities as well as the county to sign on to the subgroup idea -- at least in concept -- before moving forward with a more concrete plan. Prevetti said it's not a problem if one or two smaller cities decide to reject the subregion.

"I don't think the receiving city would put up with it, frankly," she said. "I just don't think a receiving city is going to support any dumping of allocations."

"I think if we can work together and do a subregion, that's a great first step," she said. "But whether it's going to give us 20 percent more housing -- I think that's fundamentally more (up to) market economics."

Prevetti cautioned that creating a subregion may set the groundwork for more housing growth, but it doesn't guarantee it will get built. The Bay Area is still subject to market forces, and it will be up to local developers to come forward with projects.

Council backs cross-city housing plans

New policy would open the door for cities to 'trade' obligations to build units