Capt. Herbert E. Bever of the Washington Aqueduct police wears a navy blue uniform with gold buttons and two gold bars and packs a .38-caliber Smith and Wesson on his belt.

In the last 19 years, he has never made an arrest, nor has he fired his gun.

Bever's record is no different from those of his 14 colleagues. The men charged with protecting Washington's water supply -- men whose combined yearly income is $200,000 -- have yet to arrest anyone. When asked, they find it difficult to come up with a single memorable event in the force's 40-year history.

Bever spends most of his time behind a metal desk at the green cinder block headquarters of the Washington Aqueduct treatment plant on MacArthur Boulevard. There, from 7 a.m. to 3 p.m. Monday through Friday, he ponders his mission.

"There's generally enough to do to keep from getting bored," he says. The phones are silent. A ceiling fan whirs from a corner of the rugless room.

"Kojak" this is not.

There used to be 20 or 21 members of this federal force, Bever says. Now they are down to 15. Two years ago, the Aqueduct police stopped issuing traffic tickets on McArthur Boulevard and became strictly a security force. There is one guard at the main gate. He is charged with signing in the handful of visitors to this red brick complex near the Maryland state line.

The others fill their time guarding the waters of the reservoir from children who consider it a good swimming hole. This is done around the clock, protection for the area's customers who use the 200 million gallons of water pumped each day to homes in the District of Columbia and Virginia.

It is a life with little drama. And the Aqueduct police, who are civil servants, earn a starting salary of $10,000. For these reasons, Bever says, "We get the ones other people don't want."

Even the Aqueduct police, though, can point to days of near glory. Back in the 1960s and early 1970s when D.C. police officers prepared for the waves of antiwar protesters, commotion spilled over to the reservoir.

One group of protesters threatened to pollute the city's water supply -- which also fed the Pentagon -- with a rich dose of LSD tablets. Perhaps Bever misses those times?

"I'm perfectly satisfied," said Bever, clasping his hands over his paunch.

Neither Bever nor Harry Ways, chief of the plant complex, believe that the security force is wasteful. The main expense is paying that $200,000 annual payroll. The force has but one patrol car. It is used from time to time to make routine checks of the gates.

There is no jail. If a saboteur broke inside the treatment plant, the security guards could only make "a citizen's arrest," Bever said, and detain the suspect for local police.

"We're just looking to protect the water supply," chief Ways said yesterday. "That's our job . . . it's just as important as guarding a nuclear power plant."

Created in 1938 by an Act of Congress, the Aqueduct force is part of the Army Corps of Engineers and its future seems as secure as its parent organization.

Without the Aqueduct police, Bever said yesterday, "people would just walk in and take over."

Finishing up his brown bag lunch of baloney sandwiches, Bever said with a laugh: "We're a necessary evil."