About 90 percent of the nation's and the Washington-area's savings and loan mortgage lenders said they expect mortgage interest rates to stay above 12 percent through the end of the year, and one-third of local lenders said rates still would be at least 13 percent on Jan. 1, according to a survey by the U.S. League of Savings Associations.

The local lenders responded more pessimistically to the survey than the national lenders. For example, while more than 10 percent of national savings and loan mortgage lenders said their housing market is strong, none in the Washington area said so.

According to the survey of 1,500 of the nation's 4,700 savings and loan associations, more than one-fourth of the lenders expect mortgage rates be higher than 13 percent at the end of the year, and 99 percent said interest rates will stay in the double digits throughout next year.

Locally, 34.38 percent of lenders in the Washington area said rates will exceed 13 percent, 53.13 percent said rates will hover between 12 and 13 percent, and 12.5 percent said mortgage rates will range between 11 and 12 percent, the survey said.

Thirty-two of the area's 51 savings and loan lenders were surveyed, the report said.

In practical terms, the figures mean that the monthly mortgage cost -- excluding taxes -- to a homebuyer obtaining a 30-Ear, $50,000 loan at 13 percent interest would be $553.10, while it would be $402.32 with a 9 percent loan, the association said.

The release of the survey yesterday is part of the association's campaign against recent government actions to inject more competition among the lending institutions. Association President Edwin B. Brooks Jr. said the government's elimination of the quarter-point differential given to savings and loans over commercial banks has led to a shortage of money in those institutions and has contributed to high mortgage interest rates. Savings and loans had been allowed for years to grant one-quarter percentage point more on savings accounts than banks, but last May the differential was eliminated as part of an overall deregulation of the banking industry.

Brooks said savings and loans have lost $17 billion in potential mortgage funds because of the loss of the differential. He also said he hopes that high interest rates will be a major campaign issue this fall.

Interest rates for mortgages financed at 80 percent in the Washington area ranged from 12 1/4 percent at Baltimore Federal Savings and Loan to 13 7/8 percent at Arlington Mortgage Co., according to a survey last Thursday by Peeke & Associates Inc. Most of the other lenders surveyed charged rates between 13 1/4 and 13 3/4 percent.

Nearly 38 percent of local savings and loan lenders described the housing market as "depressed and stable," 34.38 percent said it was improving slowly, and 28.13 percent said the market is worsening, the survey said.

Nationally, 60 percent of the lenders said rates by the end of the year will be between 12 and 13 percent, and 28.37 percent of the lenders said the rates will exceed 13 percent. Eleven percent of them said mortgage rates will range between 11 and 12 percent, the survey said.

Despite the pessimism expressed by local lenders, 41.34 percent of those across the country said their local housing market is improving slowly while 34.9 percent said it is depressed and stable. Those who felt the housing market was worsening accounted for 13.02 percent of the respondents, and persons who said the market was strong or improving consisted of 10.74 percent of those surveyed.