The median price of single-family homes in the Washington area fell 5 percent between April 1989 and April 1990, in what appears to be the first decline in local housing prices in at least a decade.

The median price of single-family homes in the Washington area dropped to $191,985 from $202,239, after rising steadily for almost 10 years, according to real estate transaction records compiled by the Silver Spring-based real estate information company of Rufus S. Lusk & Son Inc. The study compared April 1989 new-home and existing-home sales prices with those from April 1990.

Some longtime real estate brokers said their experience confirms the figures and reported evidence of across-the-board price declines. They said some homes are selling for less than their appraised values and others are selling for less than their assessed values. They also reported they are seeing cases in which properties are selling for substantially less than similar, or even identical, properties sold for two years ago.

"For the first time in my career, and this is my 30th year in real estate, I have seen the average price of a house sold for less than it was the year before," said William Ellis, executive vice president of the residential division of the Shannon & Luchs real estate firm.

"The sales that are going through are definitely for less than what similar houses sold for a year ago, or even six months ago," said real estate broker Gail Belt of Town & Country Properties Inc.

Belt said a colonial-style home she sold in Vienna last summer for $389,000 is on the market again now with an asking price of $369,000.

"This is a deeper cut, and an all-pervasive cut, there's no doubt about it," Belt said. "I don't see any rapid bouncing back."

Rufus S. Lusk III, president of the company that conducted the study, characterized the decline as evidence of a healthy readjustment of a market that had become unbalanced and overly expensive.

He said home prices had risen so quickly in the Washington area in recent years that they had simply outstripped people's incomes in many cases.

Over the past year, real estate industry officials had noted that prices had flattened in the face of a growing inventory of unsold homes, but the April statistics provided by Lusk suggest that the glut has finally translated into declines in prices. In addition, however, the market mix has shifted from an emphasis on expensive trade-up housing to more affordable homes, which also tends to depress the median price.

Lusk said the new numbers indicated that April 1989 was what he called the "high-water mark" of the Washington real estate market. He said early indications are that similar declines will be seen when the May and June transactions are compiled.

Local home sellers are exacerbating the situation, Lusk and local brokers said, because of their unwillingness to drop prices from the levels they had hoped to obtain. Many have flatly refused to cut their prices, leaving their homes on the market for months, and that has added to the growing oversupply of unsold homes. Now, however, with the peak summer selling season well underway, many sellers can no longer hold out, they said, and are finally reducing their prices to sell. "Everybody wants to buy low and sell high," Ellis said. "But we're not in a position where you can sell high anymore."

The Lusk study found notable regional variations in the April-to-April comparison. The decline was most extreme in the District of Columbia, where the median single-family home price fell 9 percent, to $183,451 from $201,192. In Fairfax County, it fell 6 percent, to $215,934 from $230,636, and in Montgomery Country, it dropped 3 percent, to $216,446 from $224,242. Alexandria prices fell 3 percent, to $203,960 from $210,100.

The median price in Prince George's County climbed 11 percent between April 1989 and April 1990, rising to $129,192 from $116,059. Arlington County prices increased 2 percent, to $224,983 from $220,400.

The condominium market has maintained a generally stable course , with prices in some jurisdictions rising and others falling. Overall, throughout the region, condominium prices fell about 1 percent, to $105,055 from a median price of $106,006.

The Lusk study tracked median prices, the midpoint figure at which half the homes sold for more and half for less. That number is considered more statistically significant than the average price, which can be easily skewed by a relatively few transactions, such as the sales of multimillion-dollar estates.

.................SINGLE-FAMILY HOUSES........CONDOMINIUMS

AREA.............NO. OF........MEDIAN.....NO. OF......MEDIAN

..................SALES.........PRICE.....SALES.......PRICE

ALEXANDRIA

April 1989..........107......$210,100......137......$101,863

April 1990..........108.......203,960......189......117,071

Increase (decrease)...1.......(6,140)......52.......15,208

Percent change.......1%...........-3%......38%......15%

January-April 1989..344.......203,486......480......98,625

January-April 1990..331.......204,900......634......102,634

Increase(decrease).(13).........1,414......154......4,009

Percent change...... 4%............1%......32%......4%

ARLINGTON COUNTY

April 1989..........153.......220,400......175......121,860

April 1990..........138.......224,983......166......121,903

Increase(decrease)..(15)........4,583......(9)......43

Percent change......-10%...........2%......-5%......0%

January-April 1989...520......208,500......604......116,242

January-April 1990...479......208,419......618......132,744

Increase(decrease)...(41)........(81).......14......16,502

Percent change........-8%..........0%.......2%......14%

DISTRICT OF COLUMBIA

April 1989............430.....201,192......205......105,592

April 1990............336.....183,451......203......105,089

Increase(decrease)...(94)....(17,741)......(2)......(503)

Percent change.......-22%.........-9%......-1%......0%

January-April 1989..1,672.....181,452......784......96,260

January-April 1990..1,267.....186,972......738......97,497

Increase(decrease)..(405).......5,520.....(46)......1,237

Percent change.,,,,,,-24%..........3%......-6%......1%

FAIRFAX COUNTY

April 1989..........1,810......230,636.....566......114,397

April 1990..........1,396......215,934.....440......109,079

Increase(decrease)..(414).....(14,702)...(126)......(5,318)

Percent change.......-23%..........-6%....-22%......-5%

January-April 1989..6,238......219,251...1,878......112,756

January-April 1990..4,912......221,568...1,525......127,256

Increase(decrease)(1,326)........2,317.....353......14,500

Percent change.......-21%...........1%....-19%......13%

MONTGOMERY COUNTY

April 1989..........1,186......224,242.....327......101,463

April 1990............945......216,446.....303......101,315

Increase(decrease)..(241)......(7,796)....(24)......(148)

Percent change.......-20%..........-3%.....-7%......0%

January-April 1989..3,989......210,697...1,223......94,679

January-April 190...3,628......215,620...1,062......105,833

Increase(decrease)..(361)........4,923...(161)......11,154

Percent change........-9%...........2%....-13%......12%

PRINCE GEORGE'S COUNTY

April 1989............936......116,059.....183......76,572

April 1990............948......129,192.....203......76,916

Increase(decrease).....12.......13,133......20......344

Percent change.........1%..........11%.....11%......0%

January-April 1989..3,343......113,026.....721......69,984

January-April 1990..3,426......125,614.....716......68,801

Increase(decrease).....83.......12,588.....(5)......(1,183)

Percent change.........2%..........11%.....-1%......-2%

TOTAL

April 1989..........4,622......202,239...1,593......106,006

April 1990..........3,871......191,985...1,504......105,055

Increase(decrease)..(751).....(10,254)....(89)......(951)

Percent change.......-16%..........-5%.....-6%......-1%

January-April 1989.16,106......190,476...5,690......100,356

January-April 1990.14,043......192,659...5,293......108,592

Increase(decrease).(2,063).......2,183...(397)......8,237

Percent change........-13%..........1%.....-7%......8% SOURCE: Rufus S. Lusk & Son Inc.