When Herbert Runnels bought several properties in North Charleston, he thought he had found a good place to rent lots to people relocating from the nearby Trailwood mobile home park.

The properties had mobile homes on them already, with space for more, and they were adjacent to a mobile home park. But Runnels soon learned that North Charleston regulations wouldn’t allow more mobile homes on his land, and wouldn’t allow a vacant mobile home already on the land to be reoccupied.

Runnels had bumped up against a combination of city zoning rules and tough regulations the city put in place years ago, aimed at reducing the number of rental properties in North Charleston, and particularly mobile homes.

“I was shocked,” said Runnels, 62, who works at Nucor and owns rental properties as an investment. “Now I’m looking at trying to sell the property.”

The policies confronting Runnels go back to a city effort that began in the 1990s, aimed at raising home ownership.

Ray Anderson, special assistant to Mayor Keith Summey, said that in 1990 just 40 percent of North Charleston homes were owner-occupied, and the city wanted to change that.

“You don’t change those kinds of numbers overnight, but we tried to start tweaking the comprehensive plans toward that,” Anderson said.

The 2010 census found homeownership in the city had climbed to 49 percent — a large change, but still well below the state average of 70 percent.

“With more home ownership, people take better care of their properties, and values ease up,” Anderson said. “We still have a ways to go in our community, moving forward.”

Some of the growth in home ownership came from new subdivisions, some came from people buying homes that used to be rentals, and some came from zoning and land use policies that whittle away at multi-family rental properties and mobile homes.

“North Charleston should aim to acquire, whether through eminent domain, or other methods, any severely substandard mobile home parks for redevelopment into affordable owner-occupied housing,” the city’s Comprehensive Plan says. “It should also try to zone out scattered mobile homes within single-family neighborhoods where these uses may be driving down home values and appearance standards.”

Here’s how the policies work.

First, the city rezoned some areas, changing the rules about what is allowed on properties in different areas. For example, an area that used to allow mobile homes might no longer allow them.

Second, the city adopted an unusually tough rule about what’s known as a non-conforming use, such as a mobile home located on land zoned for single-family homes.

So long as a mobile home is occupied, it can stay, but if it’s vacant for just six months, it can’t be reoccupied, and if a mobile home is removed from the property, it can’t be replaced.

For example, Herbert and Stanley Frasier own a property on Kraft Avenue in Charleston Heights, and were planning to rent a mobile home there to an elderly woman, but learned after she had moved her furniture in that the city would not allow the home to be occupied because it had been vacant more than six months.

The Frasiers have filed a legal challenge.

“What happened here was, my client simply had a tenant and wanted to reconnect the utilities,” said Arthur McFarland, the Frasiers’ attorney. “The mobile home, despite its condition, couldn’t be used for its only purpose” because of the city’s rules.

Those regulations are one reason the city has seen a large drop in the number of mobile homes. North Charleston accounted for two-thirds of the decline in the number of mobile homes in Charleston County from 2001 to 2011.

And that was before Trailwood, a huge mobile home park near the airport with space for 700 trailers, shut down because the property was sold.

In other cities, non-conforming-use rules aren’t so strict. In Charleston, for example, a non-conforming building would have to be vacant for three years in order to lose its zoning, according to city Zoning Administrator Lee Batchelder.

An analysis of county property records by The Post and Courier found that the number of mobile homes in the tri-county area dropped modestly from 2001 to 2011, by 3 percent, but in North Charleston, 11 percent of the mobile homes went away.

During that decade North Charleston’s population grew by about 18,000.

One of the challenges that mobile homes present is that, often, they aren’t really mobile. If they can be moved, it can cost thousands of dollars, but older models often can’t be moved at all.

For Demitric Gantt, the combination of city regulations and the realities of moving an old mobile home will mean that the one he bought and planned to live in will have to be demolished.

Gantt bought an old mobile home for $1,500 — a real fixer-upper, a 1969 Fleetwood — and started making repairs, only to learn later that the home could not be occupied because it had been vacant more than six months.

“I’m stuck between a rock and a hard place,” he said. “I invested money in it, and my labor fixing the roof and other things.

“When I went the city to get the permits to rewire the trailer they gave me some excuse about zoning,” Gantt said. “They took the air out of my sails.”

Anderson said property owners need to do their due diligence before buying land or a mobile home, and he said it’s a bad idea generally to live in a mobile home that pre-dates modern building codes.

“We’ve been careful to watch the pre-1976 mobile homes,” said Anderson, explaining that mobile home construction codes changed that year. “We want those out of the city because they are unsafe.”

“It’s not that we’re trying to be callous or insensitive,” he said. “We still have mobile home parks and multi-family in the city.”

Even with the substantial decline in mobile home ownership in North Charleston, county records show there were nearly 4,000 mobile homes in the city limits in 2011, and another nearly 800 in the North Charleston Public Service District.

In contrast, there were about 1,550 mobile homes on Johns Island that year, and just over 500 in West Ashley. The Goose Creek area is home to more than 4,000 mobile homes, but no other area in Berkeley, Charleston and Dorchester counties comes close to the numbers seen in North Charleston.

Anderson said North Charleston is sensitive to the need for affordable housing, but also wants safe housing. He said the city has often found code violations at mobile home parks, and shut some down.

“It’s a fine line, because not everybody can afford a single family home,” he said. “Some of these locations are so egregious, it’s hard to believe the living conditions.”

Reach David Slade at 937-5552 or Twitter @DSladeNews.