A key D.C. City Council panel yesterday effectively closed the door on any property tax relief for Washington homeowners this year by agreeing that the only way to avert a $20 million-revenue shortfall next year was to keep property tax rates the same as this year for both business and residential dwellings.

With assessments up by about 20 percent, the owner of an average District house assessed at $85,920 will pay an extra $165 in real estate taxes in the coming year.The bills are due in two payments -- one on Sept. 15 and the other next March.

The council's Committee on Finance and Revenue took no formal action after yesterday's public hearings, but the members said they were left with few alternatives to Mayor Marion Barry's requested tax rise, via increased assessments. The committee is scheduled to meet again on Monday, and the full council must approve the property tax rates at its meeting Tuesday.

The proposed 1982 tax rates are $1.22 per $100 of assessed value for owner-occupied residential property; $1.54 per $100 of assessed value for rental property; and $2.13 per $100 of assessed value for commercial property.

In some previous years, especially near election time, the practice has been to lower the tax rates as assessments rise, so that homeowners pay only tax increases resulting from inflation.

"This is a clear example of a 20-percent tax increase without the appearance of raising taxes," said council member Betty Ann Kane (D-At Large). "The council made a commitment when we passed the [fiscal year] 1982 budget not to lower the property tax rates the way we have in previous years."

Council member John Wilson (D-Ward 2), the finance committee chairman, said that property tax relief this year was "desirable, but it's just not likely." Wilson said that the only way to grant some relief to homeowners would be to shift the tax burden someplace else, such as on businesses, which are already facing a 28 percent property tax rise because of the higher assessments.

Even with the higher taxes, however, statistics from previous years show that since 1977, property tax bills in the city have increased by only 46 percent, while assessments rose by about 145 percent in that time.

"The best we can do as a government is to hold the line on all property tax rates," said Carolyn Smith, director of the Department of Finance and Revenue.

Some Finance Committee members said that homeowners should take greater advantage of the property tax relief provisions that are available, such as income-tax deductions for local property taxes that are paid and deferred payments, both for persons who fall within certain income brackets.

But two D.C. taxpayers who appeared at yesterday's hearing said that even with the deferred payment plans, the higher taxes would impose a financial hardship on homeowners, especially squeezing older and retired D.C. residents living on fixed incomes.

Blanco High, a retired federal government worker who said he was representing several retired homeowners who live in the 3800 block of 24th Street NE, said that the assessed value of his small, two-bedroom home has increased from $47,128 to $52,359 in the past year. That increased assessment will raise his taxes by $61, while he still receives less than $10,000 a year in pension and retirement benefits.

"You're holding the rate the same as last year, but I'll pay more taxes," High said. "We won't have any place to live if this keeps going up." CAPTION: Chart, Tax bills in D.C. this chart shows how changes in assessments and rates have effected the property tax bill for an average home in the city, WHICH IN 1977 WAS VALUED AT $35,091. By Gail McCrory -- The Washington Post