An inmate of the Arlington jail committed suicide yesterday by hanging himself with a bed sheet from the bars of the isolation cell where he had been held since Wednesday. It was the second suicide at the jail this month and at least the fourth attempt.

The inmate, identified as Dale Martin Evans, 24, a District resident, was being held under $2,000 bond on charges of forgery, uttering and grand larceny. He was found hanged about 4 p.m. and died an hour later at Arlington Hospital after unsuccessful attempts to revive him.

County Sheriff Jim Gondles described Evans as someone who had used drugs, but said he had given no indication of suicidal tendencies. The sheriff said he knew of no reason for the suicide.

Gondles said Evans was placed in the isolation cell, less accessible and visible to jail personnel, only because the jail was overcrowded and no other space was available. The detention facility, near the courthouse, was built for 120 inmates but was holding 174 over the weekend, the sheriff said.

Evans' suicide came 17 days after Gregory L. Warfield, 27, the son of a mortgage banker, was found hanging from a bed sheet in his cell. Efforts to revive Warfield failed. A few hours after Warfield was found Jan. 8, Skip Adams-Taylor, 20, a Washington man who had just been convicted in a strangulation murder, was saved by deputies who found him dangling from sheets in a nearby cellblock.

In an interview last night, Gondles said that "one or two" unsuccessful suicide attempts were made last week at the jail.

The hangings are the most recent problem to confront the 33-year-old sheriff, who said last night that the year and 25 days he has been on the job since his election "seems like 25 years."

In December, after vigorous and widespread criticism, Gondles gave up his policy of strip-searching all persons brought into his jail to ensure that they were not carrying drugs or weapons in body cavities.

The sheriff, who said ruefully after the first hangings that the "thought 1981 was going to be a better year," said he would meet again with staff members to try to find methods of preventing further incidents.

At the same time, he expressed the belief that while suicides may be postponed they cannot be prevented.

"You can watch 24 hours a day, and take your eye off for one second and they're going to kill themselves," he said.

One possible solution, he suggested, might be to obtain evaluations of new inmates from a psychologist.

Of the 174 persons held in the jail over the weekend, Gondles said, 31 were prisioners assigned to state custody for whom the state corrections system had no room. If not for the over-crowding, he said, Evans might have been held in a receiving cell, which "may have made it easier for use to check on him.

Although the isolation area, where Evans was held, is less accessible than other parts of the jail, state regulations call for a deputy to make the rounds every 30 minutes. Gondles said. He said that rounds are made more frequently than that in the Arlington jail and that Evans was seen by a deputy 20 minutes before he was found hanging.

The inmate, whose wife was also being held at the jail, according to Gondles, was found by a paramedic who was dispensing medication. Gondles said that Evans apparently had stood on his bed, knotted the full sheet or one or more strips of the sheet to the bars, and stepped off the bed.