Washington area lenders lowered their interest rates for new home mortgage loans by an average of half a point over the past two weeks -- the first dip in the rates after months of increases.

A survey released yesterday showed that the average interest rate on an 80 percent home mortgage loan was 16.2 percent this week, down from an average of 16.7 percent two weeks ago.

The drop is not expected to prompt a swarm of loan applications, however. On an $80,000, 30-year mortgage, the decrease would save a home buyer only $30 a month off a mortgage payment of about $1,120 -- still more than most buyers are able to pay.

Lenders and financial experts said it is too early to tell whether the slight drop foreshadows a summer of more affordable home mortgages.

The survey, conducted by Victor J. Peeke of Interest Data Reports, a private mortgage reporting service, showed that about 40 percent of area lenders still making mortgage loans lowered their rates this week.

Of the 222 lending institutions Peeke surveyed, well over a third -- about 38 percent -- said they are not making any new loans, however. About half said their mortgage windows are open to all customers, and 12 percent said they make loans only to savings customers or on a case-by-case basis.

Peeke found rates ranged from a low of just over 14 percent to 17 1/2 percent.

"I'm certainly not confident that the decline is permanent," said Thomas Owen, president of Perpetual Federal Savings and Loan, the area's largest savings association. Owen said Perpetual has quoted a 17 percent interest rate for many weeks now, and has no plans at the moment to lower it.

"I think the consensus is that rates have peaked, but that it will take another three weeks to see if it's temporary or a roller coaster that's going to continue to go up and down," said a spokesman for the Metropolitan Washington Savings and Loan League. "This may just be a temporary aberration."

Walter Preston, who runs a survey similar to Peeke's and publishes Builders, Bankers and Realtors magazine, said his survey also showed a small decline in interest rates over the past two weeks.

"This is the first good news I've been able to talk about in a long time. It may be time for some guarded optimism," Preston said. "Realtors say that activity is starting to pick up."

Economic analysts point to recent declines in the prime lending rate as an indication that interest rates may have peaked and may edge down slowly as an expected recession begins.

Several lenders interviewed said they dropped their rates a bit this week because the Federal Home Loan Mortgage Corp. and the Federal National Mortgage Association, which make funds available for residential mortgages by buying mortgages from lenders, both reported declining interest rates in recent weeks.

For the first time in four months, the mortgage association's auction last Monday produced a lower interest "yield." At auctions, lenders bid for the right to sell mortgages to the association, known as Fannie Mae, within the next four months. Based on its judgment of market conditions, Fannie Mae sets a minimum cutoff point, and buys only those loans that yield an interest rate above that point.

"I think this tells us lenders think rates might come down," a Fannie Mae spokesman said. "It's an indicator of what lenders think rates will be like in coming weeks."

A spokeswoman for the congressionally chartered Federal Home Loan Mortgage Corp., known as Freddie Mac, said its interest yield also has declined slightly in the last few weeks. Freddie Mac rates are more an indication of the current market, she pointed out, because lenders must sell their mortgages within 60 days.