Q: Having just arrived in Washington, we were astounded by the high cost of housing. We are scheduled to stay here two or three years, but have no definite plans afterwards. Should we rent an apartment or buy a house?

A: It's hard enough to give legal advice, but since you asked, let me venture an economic forecast. I am firmly conviced that the Washington area is a good growth area, and if you afford the down payment, you should buy now.

Prices have risen at least 10 per cent annually here in recent years. Add this inflationary spiral to the tax benefits of home ownershi and you can understand why I think it's better to buy.

Of course, there are times when renting makes more sense. For example, if you are in retirement on a fixed income, you may find that rising property taxes and utility cost may be too much for your budget.

Additionally, if your income is such that you take the standard deduction or don't need additional tax benefits, you should do your own arithmetic on the question of renting or buying. After all, if you can find an apartment at a reasonable rental, you can term Certificate of Deposit adn end up just as well.

You suggest you may be leaving the area in a couple of years. This should not affect you decision to buy, however. Let's suppose you purchase a $70,000 house today. In three years, it should be worth at least $85,000. If you move to another city, why not consider renting out your house?

Under the tax laws, you now have 18 months from the time you buy a house in which to sell your present residence to defer your tax profits. Thus, if you are a reluctant landlord, try it for awhile. If you don't like it - or if it causes too many problems - you still can sell within the 18-month period.

But let's look at the benefits of renting your home.

First, you will be keeping a very good investment. Remember, a values should be rising steadily in this area for some time.

Second, in addition to the usual tax deduction for real estate taxes and mortgage interests, as a landlord you can also depreciate your property. You will be surprised at the tax savings this produces.

Finally, since your property is going up in value, you should consider refinancing periodically. You can pull out enough money to enable you to buy another house, remodel or refurbish your present house, or just bank the money for another day.

Thus, i strongely recommend you consider buying a house or a condominium during your stay in Washington.

A few years ago the Department of Labor published a pamphlet entitled "Rent or Buy Evalating Alternatives in the Shelter Market." This publication will assist you in doing the necessary arithmetic to determine the finances of renting or buying.

But, mathematics along should not be determining factor. There's a Washington fever that hits many of us, and you may find that your three-year term will stretch out indifinitely. In that case, can there be any question of buying or renting?

Benny L. Kass is a Washington attorney. Write him in care of the Real Estate Section, The Washington Post, 1150 15th St. NW, Washington 20071.