Margarette Marshall, who lives in a decaying rowhouse at 1532 5th St. NW, receives $203 a month in public assistance to feed, house and clothe herself and her two children. But her gas bill last month was $207.46.

Louise Durham and her husband live four houses away in a similar row house and have a combined monthly income of $940 to pay the bills for themselves and their six children. Their last month's gas bill was $237.

The story is the same for the other six families who live in poorly insulated homes in the block in the Shaw neighborhood not far from downtown Washington. All their gas bills sky-rocketed in last month's bitter cold wave.

Their cases are somewhat unusual. But it dramatically illustrates how the high costs of this winter's weather are now coming home to roost in utility bills throughout the area. The costs are hitting virtually everyone who lives in a house in the Washington area, throwing tens of thousands of family budget out of whack.

Gas, oil and electric fuel supplies report many customers are receiving their highest heating bills in history this month.

Several fuel oil suppliers contacted yesterday, for example, said residential oil usage was up 42 per cent over January 1976. Washington Gas Light Co. reported its typical home customer was sent an $84.98 bill for January, compared with typical bill of $65.16 for the same month a year ago.

Although Potomac Electric Power Co. (Pepco) has no complete figures, spokesmen estimated the typical electrical heating bill in the area will increase from 28 to 35 per cent for the month. They had already increased dramatically in December as the first wave of the coldest winter in recent memory hit. In suburban Maryland, for instance, the typical homeowner with electric heat paid $107.80, compared to $82.82 the previous year.

"This is the highest I've ever gotten," Jack Koerner, who lives in an all-electric home in Wheaton, said. "I don't know if it will ever end. It seems the rate goes up as fast as the kilowatt usage."

Customer unrest was reflected in the number of telephone complaints received by Pepco. Spokesman John Grasser said the company received 18,394 complaint calls last week, 40 per cent more than one year ago. "That's probably directly attributable to the cold weather," he said.

Some fuel oil suppliers have relaxed bill collection efforts or offered extended payment plans to hardpressed consumers.

"The people this is really hurting are those on fixed incomes," said Richard Fadeley, part owner of Colonial Fuel Co. which serves 6,000 residential customers in Virginia, Maryland and the District. "A lot of people simply can't afford energy at today's prices."

Nowhere is this more evident than on 5th Street NW where Margarette Marshall and Harry Rosser live. The families there agree with the gas company on the cause of their high bills - the weather has simply been very cold and the old two-story homes are poorly insulated.

"This bill too much, but what can you do about it?" lamented Rosser, who received a $98 bill in January and is dreading his February bill. "You pay it or else. The real estate owner is not doing anything for the windows. All the air comes through the windows and up through the floors."

He and others on the block claim they've kept thermostats between 65 and 70 degrees for weeks, and they use kitchen stoves only for cooking.

"I have rags all around the windows. Everywhere I can stick one to keep the air out, but it doesn't seem to do any good," complained Ophelia Davis of 1520 5th St. NW yesterday.

Her February gas bill was $223. "I turn my gas down during the day because we're not home," she said. "I turn it back up to 70 degrees in the evening, but I don't put it any higher than that and I turn it back down at night."

She asked the gas company to make sure her bill was correct. "I never got a bill this high before," she said. Her gas bill last February, a relatively mild month, was $133.

Washington Gas Light spokesman Charles Krautler said the company offers a special program to install insulation. About 2,500 customers have used the service, at an average cost of $300 or $400 each, since October, 1975.

But few people in the Shaw area can afford that.

"We're trying to keep the bills and then rent up, but it's really hard," said Louise Durham. To do this, she said she can afford to buy her six children clothes only at Easter and Christmas. Otherwise they wear hand-me-downs.

Margarette Marshall, whose only income is her welfare check, is baffled about how to cope with her $207.46 fuel bill.

"I'm not paying $200," she said. 'My check isn't but just over $200 and I have to pay rent and buy food, too."

A gas company spokesperson attributed the high bills to the "poor condition of the houses. Some of the older houses are like sieves. The heat goes out through the cracks in the walls."

The official added that the colder the temperatures the more heat it takes to maintain even a 65 to 70 degree temperature.

She said because of the high gas bills, the utility company's customers have been told to call the company and arrange to pay installments.