As morning worship services began at the First Baptist Church of Laurel yesterday, water was pouring down the inside walls, saturating the carpet in the sanctuary and splattering congregation members.

The untimely precipitation did not ruffle church members, according to Pastor Frank Perry, because they've come to know that when it's raining outside, it generally rains inside the church.

Yesterday's rains, which prompted flash flood warnings in the metropolitan area, actually did little more damage than force most area residents to stay indoors and cope with routine problems of a rainy day, according to area officials.

Between 2 and 4 inches of rain fell on the metropolitan area yesterday - more rain than had fallen in the area in the previous 17 days of December, weather officials said.

The worst problems caused by the drenching were of the magnitude of flooded basements and back-up sewers, area fire and police spokesmen said.

Arlandria residents initially were alerted to prepare for evacuation by bullhorn-bearing police and a wailing siren. But the water level in swelling Four Mile Run never reached the 9 1/2-foot mark, the level at which the residents are actually forced to leave. The highest level reached yesterday was 8 feet, Alexandria officials said.

Some Arlandria residents nonetheless prepared for the worst by moving their cars and others valuables to high ground. Pat and Morris Shweky, owners of Robcyn's, a clothes store at 3823 Mount Vernon Ave., Alexandria, spent the afternoon moving racks of clothing from the first floor of the store to the second. They said they lost $100,000 in merchandise in the last flood.

Fire officials in the District of Columbia said they received dozens of calls from residents seeking help with the flooding in their basements. The officials said the fire department responds to such calls only if the flooding threatens to cause an electrical fire.

District of Columbia fire officials spent about an hour yesterday afternoon mopping and shoveling out water from Oma Lewis' basement apartment at 1633 d St., SE, where she has lived for the last two months. "It's a shame . . . all my furniture is ruined," said Mrs. Lewis as she watched water seep through the corners of her floors.

In another incident, dozens of residents in the Clifton Terrace apartments at 1312 Clifton St. NW found themselves out in the rain when they were forced to evacuate their building after an electrical fire broke out at about 1:30 p.m. in the basement. The fire, which turned out not to be re- lated to the heavy rains, nontheless left residents with no hot water or electricity. No one was injured, fire officials said.

In Maryland, fire officials reported that most complaints of flooding and backed-up sewers came from the Laurel area. According to Arthur Brigham, spokesman for the Washington Suburban Sanitary Commission, Laurrel and other older communities in Montgomery and Prince George's counties usually are the hardest hit with sewer and flooding problems during rainstorms because the drain pipes in these communities generally are older and smaller.

IN addition, there are more homes with basement drains that feed into the WSSC sewer system in the older areas of the counties, brigham said.

Weather forecasters said the precipitation yesterday was due to the interplay of a complex low pressure system that extended from the Ohio Valley to the Carolinas and a high pressure system over the Hudson Bay.

Rain is expected to continue throughout the week, according to the National Weather Service. Snow is not expected. Temperatures will reach the mid-40s today with light rain ending sometime this afternoon, forecasters said.

"At this time, the chances of a white Christmas appear very small," said forecaster Harold Hess yesterday.

Also contributing to this story was Staff Writer James Lardner.