In a world where citizen complaints often get lost in a bureaucratic maze, Shirley Furbush's telephone inquiries touched a nerve - leading to Thursday's disclosure that the District of Columbia's utility regulators have failed to audit Pepco's fuel adjustment charges for a year.

Furbush's efforts set officials scrambling to investigate the fuel adjustment to insure it is not being abused by the electric company.Under the fuel adjustment clause, Pepco automatically passes through to customers about $100 million in fuel costs.

"It was purely accidental," Furbush said in an interview. Flushed with that success and basking in publicity, she says now she wouldn't mind working with newly elected mayor Marion Barry on utility matters.

Here's how it all happened:

Shocked at their high utility bills, Shirley Furbush and her husband, Melvin, sat down with their two children last summer to discuss the problem. The family plotted out a strategy to keep electric and gas bills down this winter in their three-bedroom house in Northeast Washington.

"The kid's started cutting off the TV upstairs when they were coming downstairs," she said. "We cut off some of the lights in the chandelier, and we'd wash dishes just once a day, before we went to bed. We used 7-watt night lights instead of a lamp. . . ."

Their goal was to keep their electric bills below $20 a month, and they began meeting the goal.

To cut their gas bills, which ran about $100 a month last winter when they kept the thermostat at 68 degrees, they decided to keep it down to 64 degrees this winter.

In the midst of all this effort, a Pepco bill arrived charging the Furbush family $5.20 for "fuel cost" on top of an $8.58 "kilowatt hour charge" for electricity actually used. While the bill was not large, the fuel cost portion mystified and infuriated Shirley Furbush.

First she called Pepco, whose representative explained that the fuel cost adjustment is a pass-through of the fluctuating costs Pepco must pay each month for coal and oil to burn in its generating plants. He explained roughly how the cost is calculated each month, but when Furbush asked to see the detailed reports and information personally, "Pepco indicated I could not see it."

So Furbush called the D.C. Public Service Commission, which regulates utility companies. She talked to an auditor and the chief accountant and kept pressing her questions until they told her that Pepco's monthly reports on its fuel adjustment - which the staff is supposed to audit monthly - had in fact not been audited since November 1977.

This was news indeed, but Furbush didn't realize how important her discovery was until she called the commission chairman, Elizabeth Hayes Patterson, to ask why the audits were not being conducted.

"At first Patterson disagreed with me," said Furbush. "She said, 'Let me check this out and call you back.' She called the next day and said, 'I hate to tell you, but you were right, and we were wrong.'"

Patterson, who recalled the conversation the same way, ordered immediate action to bring the audits up to date.