The manufactured-housing industry has launched a national campaign to convince local officials to change zoning laws they say discriminate against factory-built homes.

But industry officials in Maryland and Virginia say it is faster and more practical to change laws on the state level or to challenge local laws in courts than it is to educate everyone in the country about the difference between a manufactured home and the old standard -- the mobile home.

"An educational campaign would help Maryland, but only slightly," said Leonard S. Homa, counsel for the Maryland Manufactured Housing Association, last month. "The economic reality is that a lot of people simply aren't going to listen, and they influence what the local politicians do."

Like most of the country, the majority of counties in Maryland and Virginia do not allow manufactured homes to be placed in residential areas, said Homa and Virginia officials. Instead, factory-built homes are relegated to the dwindling number of trailer parks -- most of which straddle commercial zones.

The local exceptions are Montgomery and Prince Georges counties, which do allow them to be placed on residential lots, as long as the homes conform to zoning laws.

The confusion between trailers and manufactured homes rankles the manufactured-housing industry, which has grown steadily in the last decade.

A trailer, they say, is often perceived as narrow boxcar of a home, surrounded by trash, an ancient automobile on blocks and a few pink flamingos on the lawn.

But manufactured homes are often twice the size of trailers and include such amenities as skylights, cathedral ceilings and wood-burning fireplaces.

The average income of a family that owns a manufactured home is $21,000, said Ron Dunlap, executive director of the Virginia Manufactured Housing Association. "These aren't the working poor," he said. "They are more white collar than blue collar."

Although trailers and manufactured homes are built to slightly different building codes, the real difference is that trailers are usually owned by the resident, who rents the land upon which they sit; most manufactured homes are on lots that the residents also own.

Industry officials argue that a manufactured home is no different from a home that is built on site, except that it is less expensive. But, in the past few years, many localities have disagreed, said Susan M. Fiske, spokeswoman of the industry's national association.

"These restrictive zoning ordinances date from a time when manufactured homes were 'mobile' and designed to be towed by the family car," she said. "Many local officials still don't realize that manufactued homes have come a long way."

So far, 11 states have passed laws allowing manufactured homes to be placed in residential zones, as long as the houses conform to zoning laws. In another five, the highest state courts have allowed manufactured houses to be placed in residential zones.

"It is more practical to work for state legislation," said Homa. "It is almost hopeless to try to educate the masses." Maryland does not have legislation regarding manufactured homes pending on the state level, said Homa. But, he said, it is possible that such legislation will be introduced within the next few years.

The Virginia legislature passed a resolution in 1983 that urged localities to take a second look at how they deal with manufactured homes, said Dunlap. However, he said, most Virginia counties, especially in the northern part of the state, have actually hardened their resolve against manufactured homes.

Now, legislation allowing manufactured homes in residential zones is being prepared and is expected to be introduced in the next session, said Dunlap.

The nationally sponsored campaign is aimed purely at educating officials and their constituents about manufactured homes, including what they look like and what sort of people live in them, said Fiske. She said information packets are being distributed across the country as part of the campaign.