IF YOU EVER use a bank in the District of Columbia, you have a stake in a decision scheduled today by the D.C. Council. If you believe in opening up more chances for consumers to find lower rates on loans, higher rates on deposits and greater availability of credit in this city, you have a strong interest in legislation that would permit banking in the District by any bank in the country, with reciprocal rights for D.C. banks. But don't be fooled by a half-baked proposal preferred by those city bankers who want to pick and choose their own regional markets -- and exclude big banks that might give big breaks to customers.

This regional idea amounts to a financial gerrymandering. It would permit only banks in a southeastern region of the United States to participate in interstate banking. The sleeper in this -- the part consumers should care about -- is that the big banks, those that could offer the best advantages to individual customers, would be barred from competing here. Such a restrictive proposal also would kill serious efforts to make this city an important center of national and international finance.

Those local bankers and council members who are pushing the strictly regional idea contend that large banks might swallow up little local banks. It's a good fear tactic, but nothing more; evidence elsewhere doesn't support this argument. In fact, when New York state agreed to let the big New York City banks compete throughout the state, Citibank was unable to capture more than 3 percent of the upstate market. What really happens -- and helps -- is that competition becomes more keen, and that offers the consumer a better market in which to shop for a banking service. As Citicorp and others propose, legislation should include definite provisions for the introduction of complete inerstate banking.

Those D.C. Council members who understand and support this consumer interest should insist on a complete interstate banking agreement to take effect as quickly as possible -- and should reject all efforts to shortchange the city with any narrow, strictly regional approach.