The Residences at Holden Hills, a 48-unit condo development in the town of Holden, originally was marketed to people 55 and over. That age restriction since has been lifted.

The housing slump is pushing some developers who planned age-restricted housing to open up some communities to a younger pool of buyers.

Developers in municipalities from Hopkinton to Holden who have received permits for so-called active-adult developments designed for people 55 and older are asking towns for permission to lift age restrictions.

The requests are forcing towns to decide whether to refuse such requests and leave a development empty, or work with struggling developers and face the possibility of an influx of families and school-age children.

“[Towns] don’t want to see a failed development in their community, so I think most boards are trying to be somewhat receptive to the problems that a developer has,” said Paul Cusson, a developer and consultant. “They don’t see it as their responsibility to bail the developer out but [by] the same token, it’s within their community and they want to make sure they’re doing the best thing for their community.”

The issue has emerged as the number of age-restricted housing units in eastern and central Massachusetts has ballooned during the last seven years. The popularity of such developments has been driven partly by demographic trends that reveal growing numbers of baby boomers, those born between 1946 and 1964. Developers wanting to tap into that lucrative market have pursued 55-plus housing.

But industry experts also say the developments have sprung up in many Bay State communities because town officials encouraged age-restricted housing. Cash-strapped towns, worried about the cost of educating children, offered incentives and passed bylaws for housing designed for people 55 and older. That type of housing was less likely to attract families with school-age children.

“A lot of developers saw [age-restricted housing] as the path of least resistance in getting permits,” said Cusson, principal of New Bedford-based Delphic Assoc.

However, with home sales slowing, prices dropping and a glut of for-sale properties, some builders can’t sell units.

“Developers now have a limited pool of potential buyers and it’s become extremely difficult financially to sustain a development when you have those [age] limits,” said Cusson.

There were 150 age-restricted or active-adult communities in 93 communities in eastern and central Massachusetts either in existence or under construction, according to a 2005 report written by researcher Bonnie Heudorfer.

The report, which was done for Boston-based Citizens’ Housing and Planning Association, showed that those projects included over 10,000 units. There were an additional 14,000 units in 172 developments that were planned, proposed or in the permitting process, according to the CHAPA report.

Heudorfer said suburban communities encouraged that type of housing by offering incentives like density bonuses and establishing specific zoning to allow for age-restricted development.

More than 80 communities had zoning for age-restricted housing, and from 2000 to 2005 more than 30 communities had adopted zoning or rezoned land to allow for active-adult communities, according to Heudorfer.

While the active-adult housing built in the late 1990s was well received, the sheer volume of new age-restricted units coming onto the market would create a lot of competition, Heudorfer’s report noted.

“Any development that wasn’t well located, well designed and well priced was unlikely to succeed,” Heudorfer said.

A Community ‘Benefit’

The report’s predictions appear to be coming true in some cases.

In Holden, developer Roger Kane received a permit two years ago to build a 48-unit condo complex for people 55 and over but had trouble finding buyers.

After about a year of marketing the condos, Kane asked Holden town officials for permission to lift the age restriction because he couldn’t sell any units.

The town decided to eliminate the age restriction, but in exchange, Kane had to agree to a conservation restriction on a 110-acre golf course he owns that abuts the condo complex.

“We didn’t want a building to sit there empty, and obtaining a conservation restriction on 110 acres was huge,” said Pamela Harding, Holden’s town planning and conservation agent.

Harding said town officials feared if the condos failed, the developer would build on the abutting land to make up for the loss.

“Being that the pros kind of outweighed the cons of lifting the age restriction, we felt it benefited the community,” she said.

The development, renamed The Residences at Holden Hills, has been marketed to buyers of all ages for a month-and-a-half. In that time, 10 units have been reserved, according to Steve Levine, an agent with RE/MAX First Choice in Northborough.

Like Kane, developer Miraj Ahmed had difficulty attracting offers on 56 condos he planned to build in Hopkinton.

After over 18 months of unsuccessfully marketing the project, the developer decided to take a fresh approach.

“We went back to the [Zoning Board of Appeals] and said, ‘This is going to turn into an economic disaster if he can’t sell any units,'” noted Cusson, who is consulting Ahmed.

The developer redesigned the project to include 16 single-family homes and 28 condos with various floor plans. The ZBA will have a public hearing to discuss the new plan Sept. 26.

“I give credit to the board. I think they’ve been very difficult but receptive to work with,” said Cusson.

“I think by being difficult they’re doing the developer a favor,” said Cusson, noting that the board pushed the developer to carefully redesign the development.

Robert Engler, a consultant with Stockard Engler Brigham LLC in Cambridge, said active-adult housing is a very specialized market. In order to be successful, developers must understand the unique design characteristics, pricing considerations and marketing techniques that are required, he explained.

Some of the developers running into problems are inexperienced at developing active-adult communities and don’t know the market well, he said.

“You just don’t throw it up and hope they come. If you build it, they may not come,” said Engler.

Engler worked with a developer about four years ago to eliminate the age restriction at an apartment community in Quincy.

The project, The Highlands at Faxon Woods, was developed by Roseland Property Co. It was less than a third occupied when the developer asked the city for permission to open up the apartments to younger buyers.

“[The developer] had to demonstrate that there wasn’t a market,” said Engler.

Engler said Roseland also had to offer financial incentives to tenants who were already living at the property.

Despite the increase in age-restricted communities, Engler said he believes that a market still exists for active-adult housing that is designed, priced and located appropriately. Engler is seeking to be a co-developer with Abbott Real Estate of an active-adult community in Winchester.

Winchester already has active-adult communities, but Engler said the demographics show that more can be added. According to his analysis, almost half of Winchester residents are older than 55 and another 24 percent are between the ages of 44 and 55.

In Bridgewater, Drew Dyer received a permit last May to build an 88-unit development, with a mix of single-family homes and duplexes, for people 55 and older. But Dyer said after receiving the permit, the Conservation Commission discovered wetlands on the 22-acre site, which forced him to redesign the units.

The wetlands and the housing market downturn spurred Dyer to open up the housing to buyers of all ages.

Dyer, owner of Dyer Construction, said he is currently changing the design and expects to pitch a plan for a non-age-restricted development of 88 townhouses in upcoming weeks.