CONGRESS IS wasting more time than it can afford as it slowly tries to decide what to do about the savings and loan industry. Legislation is urgently necessary, but it's blocked by an intricate quarrel between the Senate and House banking committees and their respective chairmen. Meanwhile the White House and the Treasury refuse even to acknowledge that anything has gone wrong.

This newspaper published yesterday the basic figures on the financial status of the federally insured S&Ls in this region. There are seven in the city of Washington, and, even under the very generous accounting rules that the regulators allow them to use, only two meet the federal requirement of net worth equal to 3 percent of liabilities. Under the more rigorous rules generally accepted by accountants, two of the seven have negative net worth -- meaning that their liabilities are larger than their assets. Under the same generally accepted rules, the largest S&L in Maryland, Baltimore General, also has negative net worth. Having negative net worth certainly doesn't mean that an institution will fail. But it's hardly a sign of strength. Out of some 3,100 federally insured S&Ls nationwide, at the end of last year there were 434 with negative net worth.

The basic reason is the movement of interest rates. When they shot upward, beginning in 1979, the S&Ls' investments -- mainly long-term mortgages at fixed interest rates -- dropped in value. At the same time the S&Ls had to pay out higher interest to keep attracting depositors. That squeeze led some of them -- particularly those that wanted to grow -- into new and riskier investments. Interest rates have been falling recently, and the industry as a whole is making a profit. It will probably be a very good year for S&Ls' profits. But because of the kinds of loans and other investments some of them have been making, the failures are likely to continue. The deposit insurance fund is getting perilously low.

That's why legislation is necessary, and soon. It will have to do two things. First, it will have to require S&Ls to disclose more of their financial data. How much? Enough to allow investors and the public to judge their soundness. Second, the federal insurance system will have to be revised. At present all S&Ls, from the safest to the high-flyers, pay the same premiums. It's time to introduce them to graduated rates. How about a low premium to S&Ls that stick to traditional home mortgages, but a higher one for those that want to go into commercial lending? And a still higher one -- much higher -- for those that go for direct investment in real estate development? Few taxpayers are going to be pleased to find that they have to cover the losses of failed S&Ls, if the insurance fund runs out before Congress can bring itself to act.