Nearly two years after a smattering of tiny homes popped up in the Bay Area as a peculiar new way of housing homeless people, the technique is exploding from one end of the region to the other.

Nearly 1,000 tiny homes or their close cousins — stackable modular housing units, typically with less than 200 square feet of living space — are being planned in San Francisco, San Jose, Richmond, Berkeley, Oakland and Santa Rosa.

Planners say that’s just the beginning. “We’re very excited about micro-homes,” said Lavonna Martin, director of Contra Costa County’s homeless programs. “They could be a big help. They have a lot of promise, and our county is happy to be on the cutting edge of this one. We’re ready.”

Tiny units can be built in a fraction of the time it takes to construct typical affordable housing, at a sliver of the cost, and that means a lot of homeless people can be housed quickly. In one of the most expensive housing markets in the nation, with tent-camp problems everywhere, that prospect sounds like a game-changer to officials.

Contra Costa has a $750,000 federal homelessness grant to pay for 50 stackable micro-units of supportive housing, and Richmond Mayor Tom Butt would like to see them in his city. Developer Patrick Kennedy brought a prototype of his MicroPad unit to Richmond in November, and county and city leaders say they are leaning toward choosing it.

“They’re very fine, and they make a nice-looking building,” Butt said. “They’d be good for anybody looking for housing.”

Supportive housing is the gold standard of residences for hard-core homeless people — the term refers to rooms or apartments in buildings with counselors on-site to shepherd them through the addictions or other afflictions that ruined their lives. It’s the most commonly used technique for housing chronically homeless people who have been on the street more than a year and who consume far more in police, hospital and other costs than less-troubled indigents.

The trouble is that it is expensive, costing upward of $500,000 per unit to build over about five years. Modular stackable units, often called “Lego houses” because they bolt together easily, generally cost about half that and can be assembled in less than a year.

Contra Costa tallied 331 chronically homeless people in the last point-in-time count, taken in January. Martin hopes the county and Richmond can settle on a site for the homes and sign a contract by March, and have them assembled within a year.

“These micro-homes may seem small at 160 to 180 square feet, but they’re actually pretty spacious when you’re in them,” she said. “And they go up very fast.”

Kennedy’s MicroPads have showers, beds and kitchens. Individually they resemble shipping containers, but once they’re bolted together with siding and utilities, they look like a regular building.

Kennedy offered to build hundreds of units for San Francisco, but the idea didn’t gain traction. City planners said land was hard to find, and unions didn’t like the fact that some of Kennedy’s units are built in China.

However, San Francisco officials have since moved forward with plans to build 500 units of supportive housing on Mission Street, in Mission Bay and on Treasure Island — all using tiny-unit modular housing, but this time prefabricated in Vallejo at a factory being created by developer Rick Holliday.

“We’re always interested in finding ways to do supportive housing faster and cheaper,” said Jeff Kositsky, head of the city Department on Homelessness and Supportive Housing. “There is room for experimentation, and we are now moving forward on modular housing.”

Kennedy and Holliday also have proposals for complexes of a total of 150 stackable micro-units in Oakland, all built domestically.

The tiny-home counterpart to the stackables has been a nonstarter in San Francisco because city leaders say there’s not enough open land, among other concerns. But up north in Sonoma County, the concept has been embraced. The Board of Supervisors there has approved a $1 million plan for a 24-unit village, and designers are narrowing down a list of locations.

“We need these, just like we need more affordable housing in general and more market housing,” said board Chairwoman Shirlee Zane. “We need everything, especially now (after the Wine Country fires). After we came up with our village idea, other counties were calling us wanting to know how they could do it, too. We love being groundbreakers on this.”

Tiny homes have also caught on in San Jose, where the City Council this month approved plans for a village of 40 of them for homeless people. It will be transitional housing, and the city earmarked $2.4 million to build the homes by the end of 2018. Planners are hunting for a spot to place them.

San Jose resident Sue Halloway told the council she was afraid putting the village near residences would increase “neighborhood crime, neighborhood blight (and) poor sanitation,” and predicted that it would be “a magnet for more homeless.”

City Councilman Raul Peralez said he understands such concerns, but that “there are no facts surrounding these tiny homes and whatever blight or crime they might bring, because we haven’t done them yet.”

“I tell people you really have two options,” said Peralez, who said he wants the village in his downtown district. “You can allow the homeless to live on the streets, or you can provide not only shelter but services in a confined area — with security. In my mind, that’s a way better option for managing this community in an organized way.”

One of the most ambitious proposals for tiny homes is in Berkeley, where the nonprofit Youth Spirit Artworks wants to build a 25-unit village for homeless youths. It would be the first of its kind in the nation, and the nonprofit’s director, Sally Hindman, is raising money from local religious congregations.

She hopes to have some of the units — costing $12,000 each to build — installed somewhere in 18 months. Berkeley officials say they’re open to the possibility.

“A tiny home village is very doable, very tangible,” Hindman said. “This is not something that will take years and years like typical affordable housing. We can do this even with federal money dissolving. The need is enormous, and we’re very excited.”