ROCK HILL, S.C. — A special commission trying to hash out problems created when South Carolina and North Carolina resurveyed their state line is promising to do what it can to help landowners who suddenly find most or all of their property in a different state.

The Joint Boundary Commission, which is overseeing the first full survey of the state line between the Carolinas in more than 200 years, is trying to lessen the impacts of changing school districts, utilities and possible back taxes as much as they can.

The problems cropped up because surveyors back in the 1700s didn’t have the precise instruments like GPS that allowed their modern counterparts to draw the state line within a centimeter or two. The new work shifts the state line in several areas a few hundred feet one way or the other.

That has created a bureaucratic nightmare for some. Lewis Efird’s company owns the land where a gas station was built in what he thought was South Carolina, but is now North Carolina. He said the move makes the station worthless because higher gas taxes will raise his pump prices 30 cents a gallon and the fireworks that boost his profits are illegal in North Carolina.

“We invested based on the location of the property, taxes rates, underground storage tank rules, alcohol avaibility. Had this property been in North Carolina, had we known that when we purchased the property in the early ’90s, we wouldn’t have purchased it,” said Efrid, owner of United Oil of the Carolinas.

A total of about 90 properties were affected in some way when the new survey shifted the state line along a stretch from north of Greenville and Spartanburg to where the line makes a sharp turn in Lancaster County about 25 miles south of Charlotte, N.C. Only about two dozen of them expressed concerns, said Sidney Miller, who is overseeing the work on the state line for South Carolina.

Officials with the attorney general in both states said the impact on school attendance and utilities should be fairly minimal. But one of the bigger issues could be property taxes.

Both Carolinas have rules requiring uniformity in how property is taxed. It’s likely that any accommodations made for people suddenly living in North Carolina would be scrutinized by the state Supreme Court, said North Carolina Sen. Daniel Clodfelter, D-Mecklenburg.

Most taxes for people who went from North Carolina to South Carolina would be lowered, and the state might consider giving people a rebate for a few years, said Emory Smith, a lawyer in the South Carolina Attorney General’s Office.

“I can’t assure you everything is going to be resolved in a way to the liking of each and every citizen,” Smith said. “But I can tell you we are working on it.”

Officials from both states say this is uncharted territory. Disputes over state boundaries over the past few decades have involved shifting rivers, and those that involved land were settled by the U.S. Supreme Court in the 1800s.

North Carolina officials worry they will face this problem in the future with Virginia, especially in heavily-settled areas around Norfolk, Va., and Danville, Va.

Many problems between the Carolinas have cropped up in the past 20 years as the area around Charlotte, N.C., has boomed. Land was sold with notes from surveyors warning the state line was approximated because the original 18th-century survey marked long-gone trees with hatchets.

The hardest problem to solve along the new Carolinas state line involves Efrid’s store. He estimates he deals with nine different state agencies, with vastly different regulations. He asked the commission if he could be awarded damages.

“We’re not changing the line. The line was set in 1772, and all we’re doing is finding out where it is. If the surveyors and the people who draw property deeds made mistakes, I don’t know if that gives any damage toward the state,” Clodfelter said.

But the commissioners promised to look into the matter further.

Another suggestion was to grandfather in the affected properties for at least 20 years to make sure children in school had time to graduate and people had plenty of time to solve other problems. But Karen Byrnes, who owns a six-bedroom home that moved from South Carolina to North Carolina, said that would cause its own difficulties. She has put her house on the market because of the issue and estimates her property taxes could increase by up to $6,000 a year if she has to pay North Carolina rates.

“Now we’re sitting on a piece of property that is for sale that we can’t sell. We had two potential buyers interested this week, but when they found out about all of this, they will not consider the property anymore,” Byrnes said.

While officials deal with the problems around Charlotte, surveyors are already working on the next leg. The “boundary clarification” process is complete from the mountains to the North Corner in Lancaster County, and surveyors are heading east to the Atlantic Ocean. Experts don’t expect as many problems because the area is much less urban, the instructions weren’t as complicated, and officials just discovered that surveys for some sections have been done in the past century or so.

One surveyor redrawing that line in 1905 lamented about the lack of permanent markers, saying the line was as unknown as it was when the first surveyors did their work. That same survey said they needed to re-establish the line to prevent future legal problems, said Alan-Jon Zupan, a project manager for South Carolina Geological Survey.

“Sounds familiar, doesn’t it,” Zupan asked the commission.