The D.C. City Council's Finance and Revenue Committee yesterday unanimously recommended a real estate tax rate for homeowners 15 percent below the level proposed by Mayor Marion Barry.

It ratified by the full City Council next Tuesday, the committee's action also would keep the commercial property tax rate at the same level as last year, eliminating a reduction the mayor proposed.

The rates would apply to tax bills that the city is scheduled to mail to property owners Aug. 15. The first of two installments would be due a month later.

The changed rates could pose a political quandary for the mayor, depending upon what position he adopts. Barry is due back from Africa late Tuesday, at about the same hour the council meets to act on the taxes.

If he were to veto the council's proposed rates, it could delay the mailing of tax bills.

city administrator Elijah B. Rogers said he said he did not know the mayor's position and would talk to him by telephone during the weekend.

John A. Wilson (D-Ward 2) proposed the rate changes. he said there has been no sign of opposition among council members.

For single-family homes, including condominium units, the committee recommended a rate of $1.22 for each $100 of assessed valuation. The mayor had proposed $1.44. Last year's rate was $1.54.

On an average D.C. home assessed at $60,000, the rate Barry proposed would produce a $734 tax bill, after deducting the $9,000 homeowner exemption from the home's value. Yesterday's committee recommendation would cut the tax bill by $112, to $622.

For commercial properties, including retail stores, offices and large apartment buildings, the committee recommended keeping last year's rate of $1.83 for each $100 valuation. The mayor had proposed $1.72.

Commercial properties account for about half the $11.8 billion in taxable real estate in the city.

For a third category - rental properties of up to five units (except those in which the owner occupies a unit) - the rate would be $1.54, the same as that for most such properties last year. The mayor had proposed $1.48.

All rental properties, including large apartment buildings, will be moved into this third category next year.

Under a provision of existing law that Barry proposed last year when he was chairman of the council's finance committee, the spread between the highest commercial property tax rate and the lowest tax rate on residential properties cannot exceed 20 percent.

The bill approved yesterday would remove that restriction. Under the new proposed rates, the spread would be about 50 percent.

Although the rate would be lower than last year's, it would not necessarily produce lower tax bills. Assessments on residential property have increased an average of 18 percent in the past year.

Yesterday's committee vote was 4 to 0. Wilson, David A. Clarke (D-Ward 1), Polly Shackleton (D-Ward 3) and Betty Ann Kane (D-At Large) voted for it. Willie J. Hardy (D-Ward 7) was absent.