Road Warrior

IRS back taxes may mean really getting grounded

Harriet Baskas, Special to CNBC
Larry Washburn | Getty Images

U.S. citizens who owe money to the tax man might soon be barred from flying out of the country — or even out of town.

Two separate federal government policies are converging to make traveling difficult for travelers in the unspecified future. Buried in December's Fixing America's Surface Transportation (FAST) Act is a provision that gives the IRS the right to have the State Department deny or revoke the passport of a taxpayer that has a delinquent federal tax bill of at least $50,000.

Meanwhile, another law is currently being implemented that may mean tax delinquents flying domestically could get caught up in the IRS dragnet: REAL ID — the antiterrorism measure that sets minimum standards for states that issue licenses and state identification.

Read MoreREAL ID may pose real travel headaches next year

The Department of Homeland Security has set Jan. 22, 2018, as the deadline for which all states must comply with REAL ID requirements. After that date, travelers from any states with non-compliant IDs — including Minnesota, Missouri, Washington and American Samoa — would need a U.S. passport for domestic or international air travel. Several other states like New York and Louisiana, have been granted extensions until REAL ID comes into full effect on October 2020.

"For those travelers denied passports [by the FAST Act] in states that do not issue REAL ID compliant driver's license, their options will be very limited for providing acceptable documentation for air travel," said Andrew Meehan, policy director of the advocacy group Keeping Identities Safe.

The details are in the "Revocation or Denial of Passport in Case of Certain Delinquencies" section of the FAST Act. In essence, a U.S. citizen would be in danger of having a passport request or renewal denied — or having their passport revoked entirely — if they have a cumulative federal tax bill over $50,000, including penalties and interest.

Such a scenario also includes the IRS having filed a notice of lien against that individual, or if the agency has filed a notice of levy to seize property to satisfy a debt.

'Continue to review the legislation'

Traveling abroad? Pay your taxes first!

Just how many travelers the new provisions would impact is hard to pin down. According to IRS data, there are at least 12 million taxpayers with delinquent accounts, with some of those cases referred for enforcement activity such as tax liens and seizures. Yet it's unclear exactly how many of these citizens have delinquencies above $50,000.

In a statement provided to CNBC, the IRS said it "continues to review the legislation and is taking steps to begin implementation of the program as soon as feasible," but the agency has not yet issued a timetable for implementation.

The impact on business travel could be "huge," said Kevin Mitchell, founder of the Business Travel Coalition. "The only rationale for this potential burden on business travelers would be if the government had no other recourse to collect the taxes, or to otherwise impose additional penalties as it has traditionally done."

There are a few ways to get an exemption from the rule, experts say. These include working out an installment agreement to pay tax due in a timely manner, so there's no need to cancel planned trips. Still, travel experts are concerned about the potential fallout for passengers.

"There has got be a better way to solve the problem," said Charlie Leocha, chairman of the travelers' advocacy group Travelers United, "There are so many other ways to stop tax scofflaws than trying to reduce their freedom of movement."

Clarification: Both New York and Louisiana, mentioned as non-compliant states in an earlier version of this article, have been granted extensions by DHS, which will last until REAL ID takes full effect in 2020.

— Harriet Baskas is the author of seven books, including "Hidden Treasures: What Museums Can't or Won't Show You," and the Stuck at the Airport blog. Follow her on Twitter at @hbaskas. Follow Road Warrior at @CNBCtravel.