Colorado’s rising living costs are putting a pinch not only on young adults but also their grandparents, according to a new study from SmartAsset.

Social Security payments go far enough to cover average annual living costs in only five Colorado counties, the study shows. And in 10 Colorado counties, Social Security recipients were falling short by $4,000 or more a year on average.

“This study should illustrate to folks where they are able to get the most for their money. We encourage people to think early about what they want out of retirement so they can plan and work toward making it a reality,” said AJ Smith, vice president of content for the financial planning website.

SmartAsset examined the average annual payout to Social Security recipients in each U.S. county and subtracted taxes and the average annual cost of living. Each county received an index score and was ranked.

The New England states, along with California, Colorado and New Mexico, were areas where living costs were most likely to stretch seniors relying only on Social Security. Kansas, Nebraska, Iowa, Michigan, Wisconsin and Florida, by contrast, proved among the more favorable places for seniors balancing incomes and expenses.

In Colorado, Social Security payments went the furthest in covering living expenses in Phillips, Ouray, Custer, Summit and Mineral counties. In the Denver area, Douglas County seniors fared the best.

Retirees in Phillips County — population 4,349 — had a $1,137-a-year surplus after subtracting taxes and average annual living costs from their Social Security payments.

“We are farming community,” said county administrator Randy Schafer said. “As a whole, the people who have lived here and farmed have decent Social Security checks.”

Still, Phillips County ranked only 377th nationally and in Garfield, Bent, Eagle, Gunnison and Moffat counties, retirees faced big shortfalls. In Garfield County, that gap was nearly $6,000 a year, and the county ranked 3,066th, scraping the bottom of the national rankings.

The differences result from the Social Security income that retirees receive, as well as the living costs, in each county. Social Security incomes ranged from a high of $21,147 in Ouray County to a low of $12,854 in Bent County. Living costs ranged from a high of $22,536 a year in Eagle County to a low of $16,712 in Logan County.

Social Security wasn’t intended to be the sole source of income for retirees, but many households are struggling to set money aside. A study earlier this month from the Economic Policy Institute found that 39 percent of households headed by adults aged 56 to 61 lacked a retirement savings plan outside Social Security.

And the median retirement savings of all U.S. households with working-age adults was just $5,000.

The question of whether retirees can survive on fixed incomes is growing in importance. In 2000, about 2 million people a year in the U.S. were turning 65. This year, the pace is closer to 3.5 million, and it will reach 4.2 million a year in 2025, according to the Census Bureau.

In Colorado, there were 552,188 people age 65-plus receiving benefits as of December 2014, according to the Social Security Administration. Just two counties accounted for a quarter of those retirees — Jefferson County, with 67,915, and El Paso, with 62,870. Five counties accounted for half the total.

In Jefferson County, the average annual Social Security payments fell $1,019 short of the $19,177 a year in annual living expenses SmartAsset listed. The county ranked 17th in Colorado and 1,831st among U.S. counties.

In El Paso County, the shortfall was closer to $2,000 a year. Although living costs were lower there than in Jeffco, retirees also made less from Social Security. It ranked 32nd in Colorado and 2,387th nationally.

The original story was updated to include the range of Social Security incomes and living costs in Colorado counties and statistics on participation rates in retirement plans nationally.