Connecticut car taxes are due soon. Here's what happens if you don't pay

Connecticut residents have a little less than two weeks to pay their motor vehicle taxes before state-mandated interest charges start to kick in.

Car taxes are typically due July 1, but state law gives taxpayers a 30-day grace period, in part because many municipalities don't mail bills until late June or early July. Once the grace period expires, unpaid taxes become "delinquent" and accrue interest at a rate of 1.5% per month, or 18% annually.

The penalty applies to all delinquent property taxes, not just motor vehicles, and is meant to encourage people to pay on time, according to the Connecticut Conference of Municipalities.

State law also allows municipalities to ask the Department of Motor Vehicles to place a "hold" or "stop" on future vehicle registrations for delinquent taxpayers.

Tax collectors regularly submit delinquency lists to the DMV, which flags the registration renewals of anyone with overdue motor vehicle taxes, according to CCM. Those taxpayers must get a release from their local tax collector showing the taxes have been paid before the DMV will renew an existing registration or issue a new one.

"It doesn't affect the status of their current registration," said Dave Kluczwski, president of the Connecticut Tax Collectors Association. "What it means is, if they ever try to register a car in their name, whether a new car or a renewal, they have to have all the motor vehicle taxes paid."

The registration hold isn't foolproof, however. Because Connecticut registrations are renewed every two years, some taxpayers wait until their next renewal is due before paying their delinquent taxes, according to CCM. In the meantime, they might move to another municipality or out of state, making it harder for tax collectors to recoup the money.

To track down overdue taxpayers who have moved, Kluczwski said officials can search DMV records or request forwarding addresses from the U.S. Postal Service. More municipalities have also been turning to outside collection agencies or investigative firms to collect unpaid motor vehicle taxes.

"They'll have the ability to find people out of state much better than a municipality or a tax office could," said Kluczwski, who also serves as Fairfield's tax collector.

In some cases, municipalities will file a lien to secure overdue motor vehicle taxes, though this is more commonly done with delinquent real estate taxes.

Officials say motor vehicle and personal property taxes are generally the most difficult to collect. According to CCM, some taxpayers – particularly owners of expensive vehicles – also try to avoid Connecticut's car tax by registering their vehicles at out-of-state addresses.

Those challenges have prompted some municipalities to take additional enforcement measures to improve compliance with motor vehicle tax bills.

West Haven recently restarted a program to install boots on motor vehicles with significantly delinquent tax bills. City officials said the initiative increased delinquent motor vehicle tax collections by 3.5%, recouping $513,247 in additional revenue. New Haven and Bridgeport operate similar programs.

West Haven also partnered with Berlin-based Capital Tax Recovery to identify vehicles kept in the city but registered elsewhere. Since May 2025, officials said the effort has led to more than 1,300 vehicles being registered and generated nearly $302,000 in tax revenue.

The current 18% interest rate on delinquent taxes has been in place since 1982, when lawmakers raised it from 15% to ensure municipalities were fairly compensated for late payments amid "fluctuating market rates, inflation, and collection costs," CCM said.

Legislative proposals to lower the interest rate on overdue property taxes have largely been met with resistance from municipal tax collectors, who budget "significant amounts of revenue" based upon the collection of this delinquent interest, CCM said.

Fairfield collected an average of about $375,000 a year in delinquent motor vehicle tax interest over the past two fiscal years, Kluczwski said. That total includes interest collected on unpaid car taxes dating back as much as 15 years, which is the maximum amount of time that municipalities have to pursue delinquent taxes under state law. "After 15 years, the tax is uncollectible," the Office of Legislative Research wrote in a 2008 report.

Staff writer Brian Zahn contributed reporting

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