Betty Ester worries that as reasonably priced housing vanishes, so too will Evanston’s middle class.

“We will have two classes: poor people and the rich,” said the Evanston resident and community activist who ran unsuccessfully for Second Ward alderman in 2001. “But what about the people in the middle?”

In Evanston and other North Shore communities, officials continue to balance the interests of residential developers with those of middle-class residents who are increasingly finding themselves priced out of the housing market.

In Highland Park, Ill., the city council passed an ordinance in August requiring 20 percent of new residential developments set aside as “affordable” housing, meaning it is within grasp of a family of four making between $56,500 and $90,000 per year. This came in response to an increase in the cost of living, Highland Park officials said.

“We lost a lot of rental units in the past few years, and the city’s gotten progressively more expensive,” said Howard Wender, chairman of Highland Park’s housing commission. “The city has a commitment to diversity and we’re losing it. This is a response to that.”

Much like in Evanston, Wender said residents who worked in Highland Park were being forced out because housing was too expensive. Unlike the average housing price in the city, which is about $430,000, the affordable housing must be priced at an average of $180,000.

“Our program is really targeted to people that live in Highland Park and people that work — like teachers, firemen and policemen,” he said. “For people that work in the community, they deserve to live there.”

For Evanston housing authorities, the Highland Park solution is a realistic goal. The Evanston City Council approved last year the creation of a task force with goals of researching business- and community-based incentives for affordable housing. The group includes members of the Evanston Housing Commission and elected city officials.

“There is no question that Evanston has a commitment to preserve the diversity of the community in support of affordable housing,” said Robin Snyderman-Pratt, chairwoman of the Evanston Housing Commission. “The question is, ‘How can we do a better job of capturing private sector housing?'”

Unlike public-housing projects of past decades, which were funded entirely by the government, Evanston is looking to private developers as one of its main sources to initiate more affordable housing similar to what Highland Park has done. Known as inclusionary zoning, this measure would require residential developers to designate a certain number of apartments as exclusively affordable units that appeal to middle-class residents.

“It’s a policy, a tool to create affordable housing,” said Donna Spicuzza, housing planner for the Evanston Planning Division. “It can be mandatory or voluntary.”

In both Highland Park and the potential Evanston campaign, developers have an option to waive affordable-housing requirements. Instead of setting aside units or homes, developers simply can pay a fee to the city’s housing fund.

No mandatory housing quotas have been set in Evanston yet. Once the task force has completed its study, it will present its conclusions to the Evanston Housing Commission and then the Planning and Development Committee.

“It’s sort of hard to tell what will happen, because there’s not even a recommendation yet,” Spicuzza said.

Although the inclusionary zoning method would attract both new developments and affordable housing opportunities, Ald. Joseph Kent (5th) said he was concerned for the parts of town that already are considered affordable.

“We have part of the Fifth, the Second and the Fourth wards, which are the last of the affordable frontier as it is right now,” he said. “When you look at a lot of development that comes in, with condominiums, you see a lot of people getting priced out.”

As developers buy up single-family homes in these wards, Kent said, they could price them a lot higher, limiting the possibilities for affordable housing.

“The last of this affordable housing are homes that have been here for generations that are simply being pushed out,” he said. “There will no longer be single-family homes. A lot of times they’re purchased by some developer not even acquainted with the city of Evanston.”