The Washington area in 1981 suffered its worst economic performance in the past five years, topped by a 15.7 percent jump in unemployment, according to an annual economic report presented yesterday to the Metropolitan Washington Council of Governments.

Moreover, COG estimates yesterday showed an actual decline--albeit small--in total jobs here for area residents. Apparently, it was the first such decline in area employment since the Depression years.

There also was a decline in overall government employment, at both the federal and local levels, for the first time.

"As you are well aware, the Washington region over the past year has not been spared the impacts of the nation's depressed economic conditions," said John E. Touchstone, director of COG's Department of Community and Economic Resources.

"While the number of employed residents of the Washington region remained relatively stable with a reduction of less than one percent, the number of unemployed persons jumped 11,000 between 1980 and 1981," Touchstone said yesterday. "The number of unemployed persons reached 81,000, exceeding the previous record of 80,000 in 1977."

Although employment grew by 101,000 to 1.563 million between 1977 to 1980, the number of area residents employed last year dropped by 2,000 persons, Touchstone said. The overall areawide civilian work force is still about 1.65 million.

COG board members said part of the reason for the drop in employment was that many firms hire workers who live outside of the Washington area and many people who work in the Washington area commute from areas outside of the region, partly because of higher housing prices in the city and its nearby suburbs.

In addition, the closing or bankruptcies of area firms last year, such as The Washington Star, caused some workers simply to move away from the D.C. area to find jobs, business leaders have noted. Many former Carter administration officials also moved out of town.

"The phenomenon is going to expand further and further," said D.C. Council Chairman Arrington Dixon. He said the local governments should look for ways to keep jobs for local residents.

COG Chairman Carl F. Henrickson, a Loudoun County supervisor, said he knows of two firms in his county that "pull their employes almost exclusively from West Virginia."

D.C. Council member H. R. Crawford said the jurisdictions should look at foreign workers--"green card holders"--to determine how many of them hold local jobs.

Other key indicators cited in the COG report for 1981, which also declined, were:

* Residential building permit authorizations. The home building industry "had one of its worst years ever," Touchstone said. Housing starts in the region dropped from 19,700 in 1980 to 14,900 in 1981.

* Nonresidential construction activity. Not only have high interest rates and tight money plagued the housing business, but also the usually booming commercial activity has dropped, Touchstone said. The value of such construction dropped from $1.1 billion in 1979 to $964 million in 1980 to an estimated $863 million last year. "That's a lot of money we're talking about," Touchstone said.

* Retail sales. Actual dollar amounts of retail purchases dropped $50 million from about $15.5 billion, but after adjusting for inflation based on 1977 dollars "sales in the Washington region in 1981 took a dramatic drop," Touchstone said. Adjusted sales dropped from about $12 billion in 1980 to less than $11 billion last year.