Sharon Mahoney and Tom Lipa couldn't wait a minute longer. So they got in the car, drove from Syracuse, N.Y., to Alexandria and got married - all in one day.

"I called Maryland and they said there was a 48-hour waiting period," the 23-year-old June bride said as she perched on a bench in City Hall. "So we came to Alexandria. It sounded nice."

The couple who were eighth in line all the marriage license counter yesterday, will be married again in October. The 42-year-old groom said, "We had already reserved the church, gotten the bridesmaids and everything. We didn't tell anyone we came down here. Maybe we won't tell them. It's crazy."

Elkton, Md. - Once the elopement capital of the world where heiresses married chauffeurs and slipped sleepy-eyed JP's a five-spot to keep it quiet - will have to share the instant wedding trade with Alexandria.

"It runs in spurts," said Norma Cunningham, the 55-year-old deputy clerk in Alexandria's City Hall who has issued more than 700 marriage licenses this year. "Mornings are slow, but it starts to pick up about 3. Mondays and Fridays are the busiest days." June is the heaviest month.

"About half are from the Washington, D.C. But we get a lot from out of state and a lot of foreigners. Here's one from North Vietnam marrying one from South Vietnam." Cunningham flipped through a stack of papers. "You can never tell."

The license is good for 60 days. "Some of 'em come back ripped in two," Cunningham said. "Like they had a fight and said, 'Here's what I think of you.' One man brought his piggy bank in, they were so poor. Another time a woman and a younger man came. He went out to get her wallet and never came back."

Cunningham answers the phone calls, advises couples on campsites and nearby hotels, draws maps and keeps a vase of fresh flowers on her desk for emergency bouquets.

"I felt sorry for one girl who came in," Cunningham said. "She was so pregnant we thought she was gonna deliver right here on the bench. She cried through the whole ceremony. Then another girl came in. She was 25 and on her fifth marriage."

Busy couples can end one marriage and start another - in one day.

"They'll get their divorce paper upstairs and run down here for a marriage license. It's dumb," the clerk said, "but not unusual."

Why Alexandria? "It's quaint, and there's no waiting period," Cunningham said. "You come in, get a blood test for $20, get your license for $10. Cash - no checks. Then you go upstairs to Number One courtroom or over to Nick Colasanto. They're not called Jps anymore. They're known as court appointees. They charge up to $20. After the wedding you can go sightseeing."

Across the street, 72-year-old City Councilman Colasanto, was dispensing practical advice to a couple, along with the marriage certificate. "Get a joint savings account," he lectured. Witnessing the ceremony was the couple's one-week-old baby, who gurgled on the leather sofa.

"I was asked to go to a hospital one night," said John Beall, another deputy clerk who makes nuptial house-calls. "Just as I was leaving, they called back and told me it was too late."

A death? "No," Beall said, "I went back the next morning and performed the ceremony.They rolled the incubator into the chapel so the baby could be present."

Beall, who has dressed up his four-minute ceremony with quotes from Rod McKuen, married a couple in a graveyard last year. "The girl was raised by her grandmother, who died the week before the wedding. I married the couple by the gravestone. It was weird."

Norma Cunningham thinks the tide is turning, that live-in love affairs and couples who say "I don't" will come around, sooner or later. "The number of marriages has definitely increased this year," she said. "In Alexandria, at least, marriage is here to stay."

As for Norma Cunningham's marital status - she's divorced.