Shiny new high-rises in Rosslyn, the hip condos of Clarendon and the renovated bungalows in Ballston hide a truth about the state of housing in Arlington County and throughout Northern Virginia — unless your household income is above $60,000, you are increasingly being priced out of the market.

Construction is booming and 25-to-35-year-olds are flooding into the county from the District, Fairfax County and Maryland. But even starter apartments in Arlington are moving out of range for a large portion of the workforce because incomes have not kept up with the rising cost of housing, according to a study compiled by a county task force.

The increase in Arlington rents has outpaced incomes, contributing to a crisis in affordable housing, according to the study.

The preliminary findings from the first year of a three-year review of the county’s affordable-housing situation shows that during the past 10 years, the average rent jumped 47 percent while the average salary increased 37 percent.

This year, rents are up 6.4 percent and the vacancy rate is at 1.1 percent. Average monthly rents in 2012 ranged from $1,422 for an efficiency to $2,782 for a three-bedroom apartment, the county calculated.

What it means is that a family of four with an income of $86,000 “is largely limited to 1- or 2-bedroom condominiums and townhouses,” the study said. Those who earn less are left to scramble for a unit in the shrinking pool of lower-cost apartments.

“For lower income employment sectors (such as retail, hospitality and food services), average salaries have not kept pace with the increase in average rents, contributing to an affordability gap between rent and income,” the study found.

Local officials call the growing disparity a critical issue for communities such as Arlington, one of the wealthiest parts of the Washington region and the nation. Last year, the median price of a single-family home in the county was $690,000. The condo median was $372,000.

That might not be a problem for the half of Arlington households whose incomes exceed $100,000. But the other half is split almost evenly between those who make $60,000 to $99,999 and those who earn less than $60,000.

The regional problem of affordable housing was on display earlier this month when about 3,000 people applied for 122 apartments at the new Arlington Mill affordable-housing complex on Columbia Pike. More than half of the applicants were from outside Arlington. The Arlington Partnership for Affordable Housing, one of the nonprofit organizations that receives county funds for creating and managing housing, said 89.5 percent of the applicants were from Virginia, and of that group, about 91 percent were from Arlington, Alexandria or Falls Church.

The average household income that the applicants reported was $28,679, far below the area’s median income of $75,300 for a single person or $107,500 for a family of four. Partnership officials were also surprised that 36 percent of the applicants were single; Arlington has traditionally focused on housing families, and one of the benefits of the Arlington Mill complex is that most of its units have two or three bedrooms.

Those numbers illustrate some of the reasons why the County Board called for a housing study — and why a coalition of churches has organized to put a spotlight on the lowest-earning families.

Arlington is spending about $57 million in fiscal 2014 for ­affordable-housing assistance in a variety of forms, and it negotiates with developers to set aside some of the new construction for affordable units. Its grants, including federal funds that used to be known as Section 8 vouchers, to low-income households have provided an average monthly subsidy of $548 to almost 5,000 families, including people with disabilities and the elderly.

While people of many races are represented on all rungs of the income ladder, whites predominate among those who make more than $100,000, while Asians, blacks and Hispanics in Arlington on the whole make less, the study reports, based on U.S. census data.

“Affordability will impact the demographic makeup,” said Russell Danao-Schroeder, a county staffer working on the study.

The Metropolitan Washington Council of Governments expects that Arlington will need at least 21,000 additional housing units by 2040.

Those who say government should not be in the housing business overlook an important issue, County Board member Mary Hynes said.

“The market really doesn’t ensure the long-term vibrancy of the community,” she said. “There’s a continuum here, and we need not to have gaps in that continuum.”

The term “affordable housing” means different things to different people, Hynes said. “Some people think [high-rise urban housing projects] and other people think of the building down the street where the policemen and firemen live,” she said. “We have to be sure what we’re talking about.”