Charleston County has asked the state to step in after being "flooded" with calls from residents who want to pay their 2018 property taxes before Dec. 31 because of changes in the federal tax law.

"As it stands now, county treasurers do not have the authority to accept pre-payments," a county spokesman said in an email Wednesday.

In response, county treasurer Mary Tinkler asked Gov. Henry McMaster for an emergency order that would allow her office to process the payments this week.

Tinkler urged him to take "immediate action" in a letter dated Wednesday, but under the state constitution only the General Assembly can suspend laws, according to McMaster's office.

Berkeley County treasurer Carolyn Umphlett also reported "an overwhelming amount of calls and requests concerning property tax pre-payment," spokeswoman Hannah Moldenhauer said. A Dorchester County spokeswoman could not be reached for comment. 

At issue are changes that President Donald Trump signed into law last week that will limit at $10,000 the amount homeowners can deduct for state and local taxes on their federal returns next year.

The change has triggered a rush to pay 2018 property bills before Jan. 1, particularly in high-tax states like New York and New Jersey, as taxpayers hope to qualify for the current uncapped deduction for another year.  

It isn't clear whether the move will pay off. The new law bars deductions for state income taxes that are paid early, but it does not address prepaid property taxes. The IRS hasn't yet said how it will handle the matter.

Contact John McDermott at 843-937-5572 or follow him on Twitter at @byjohnmcdermott. The Associated Press contributed to this report.