Fear of the unknown drove nearly 100 Charleston County residents to a presentation Wednesday on the future of flood insurance.

Carl Simmons, the county's director of business services, told residents at Councilwoman Anna Johnson's round-table discussion at the Johns Island Regional Library that rates for many residents will increase over the next several years because of controversial changes to the nation's flood insurance program.

He also said new flood-plain maps being created by the federal government could require more residents to buy flood insurance, or to pay more for it.

The 2012 Biggert-Waters Flood Insurance Reform and Modernization Act was designed to help get the National Flood Insurance Program on better financial footing. The reforms include the new flood-plain maps and the elimination of subsidies for policyholders. Rate increases are expected to average 10 percent, but some have shown to be much higher.

Simmons said nearly 11,000 county residents pay subsidized rates, and about 55,000 pay full-risk rates.

Willie Thompson Jr., from Awendaw, said his home is on land his great-grandfather bought in the 1800s, and he wants it to continue to remain in the family. He's concerned about a provision in the law that would no longer allow property owners who pay a reduced flood insurance rate to transfer that rate to a new owner. Thompson said he doesn't think the provision should apply to transfers between family members.

Simmons said the impacts of the law are just beginning to be realized. "Keep informed," he said. "This thing is very fluid."

The county is willing to answer residents' questions on their individual properties if they contact his office, Simmons said.

The law is going to move forward, he said, but some recent opposition might slow it down a bit.

On the state level, Rep. Leon Stavrinakis, D-Charleston, last week introduced a bill in the Legislature to prevent lenders from foreclosing on homeowners who are current on their mortgages but are unable to pay escalating flood insurance premiums.

Johnson said interest was so great on the issue that she plans to schedule another session on the matter in February.

Reach Diane Knich at 843-937-5491 or on Twitter at @dianeknich.