QUESTION: We have received a notice of assessment for our property in the District of Columbia. We are not sure whether to appeal this assessment, and want your guidance.

ANSWER: If you own property in the District of Columbia, you recently have received notice of the assessment on which your property taxes for next year will be based. The District of Columbia's 1984 fiscal year begins July 1. Taxes in the District of Columbia are due twice a year, Sept. 15 for the first half and March 31 for the second half.

It used to be that the real estate tax was based on an arbitrary percentage of the value of real estate. In the 1970s, however, the Council of the District of Columbia significantly changed the real estate tax and assessment laws. Assessments now are based on the estimated market value of your property. Although the assessments generally stayed about the same as last year--indeed some assessments went down--you still should review your own situation to determine whether to appeal.

If the assessment is more than you believe your property is worth, you have the right to appeal, providing you do so before April 15.

You should contact the Valuation and Assessment Office (727-6460) and make an appointment to speak with the agent who actually reviewed your property. He or she can tell you the methods which were used to assess the property. If you are unconvinced of the accuracy of their results, this information will be useful in designing and documenting your appeal.

If you wish to file an appeal, you must file the necessary appeal form--in person or by mail--before April 15. The appeal is heard by the Board of Equalization and Review, whose members are appointed by the mayor with the approval of the Council of the District of Columbia. If you file, you will be granted a formal hearing. At that time, the burden will be on you to prove that the assessor erred.

Several kinds of proof are available. You may present the findings of a competent private assessor (assuming, of course, that they differ in your favor from the official estimates). You can submit a survey of recent sales of properties comparable to your own, showing market values more modest than those that the city assigns. You may document past trends of income resulting from the property--subtracting for factors of increasing operating and maintenance costs, aging, obsolescence, etc.--to demonstrate a smaller rate of return than the official estimate would indicate.

Or you may point to disparate--i.e., lower--official assessments for comparable properties.

It should be pointed out that appeals based on tax rate, hardship or reasons other than market value will not be considered.

You need not appear before the board. In due course after you file your appeal, you will receive a notice indicating a time and place for you to appear before the Appeals Board. Although your presence is not necessary, if you care enough to pursue the appeal, it is strongly recommended that you appear in person (with or without your attorney) and make your presentation.

Remember that an appeal can be a complicated and technical procedure. And it must be pointed out that the appeals board has the right to raise the assessment as well as lower it once you have filed your appeal.

Before you decide which course to take, visit the Assessor's Office. The files are open during reasonable business hours, and the government officials are generally quite helpful.

The Board of Equalization and Review recently moved its offices to Room 2066, Municpal Center, 300 Indiana Ave. NW, Washington, D.C. 20001. (Phone 727-6868).

Benny L. Kass is a Washington attorney. Write to him in care of the Real Estate Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. For a copy of the free booklet, "A Guide to Settlement on Your New Home," send a self-addressed, stamped envelope to Benny L. Kass, 1528 18th St., Washington, D.C. 20036.