Three different situations
Whether and how your record clears depends on how the case ended. First, a case that ended without a conviction (dismissed, nolled, or found not guilty) is erased. Second, a low-level conviction may be erased automatically after several years under the Clean Slate law. Third, a conviction that does not qualify for Clean Slate can only be cleared by applying for a pardon.
These are three separate paths with different rules, so start by identifying which one you are in.
If your case ended without a conviction
Under Connecticut's erasure statute, if your case was dismissed, or the prosecutor entered a nolle (a decision not to pursue it) and time passed without the case being reopened, or you were found not guilty, the criminal record of that case is erased. Erasure means the records are destroyed or made confidential, and by law you may answer that you were never arrested for that matter.
A nolle is erased thirteen months after it is entered, as long as the case is not reopened. A dismissal or acquittal is erased sooner. This is also what makes a diversionary program valuable: completing it dismisses the charge, and the dismissal is then erased.
The diversionary programs page explains which program fits which charge.
The Clean Slate law for convictions
Connecticut's Clean Slate law automatically erases certain older, low-level convictions once you have gone a set number of years without a new conviction. The automatic erasures run in the background, with no petition required for eligible convictions that occurred on or after January 1, 2000. An eligible conviction from before 2000 is not erased automatically; it takes a petition.
The waiting period is seven years from your most recent conviction for eligible misdemeanors, and ten years for eligible lower-level felonies, and you must have finished all your sentences. Serious felonies, sex offenses, and family violence crimes are not eligible.
A single DUI conviction is eligible for erasure on the ten-year timeline. A DUI is not eligible only if there is another DUI conviction within the ten years following it.
Because the state has no reliable way to tell people their record was cleared, many who qualify do not know it has happened.
Cannabis convictions
Because cannabis is legal for adults, many old cannabis possession convictions have been erased. Possession convictions from January 1, 2000 to October 1, 2015 were erased automatically. Other cannabis convictions, from October 2015 to July 2021 or from before 2000, can be erased by filing a petition with the court. If you have an old cannabis charge on your record, it may already be gone.
Current drug possession charges are a different subject; that page covers what happens to a case that is open now.
Pardons for everything else
A conviction that Clean Slate does not reach can be cleared only through a pardon from the Connecticut Board of Pardons and Paroles. A full or absolute pardon erases the conviction as if it never happened.
You apply to the Board, there is a waiting period after your sentence ends, and the Board reviews your record, what you have done since, and sometimes holds a hearing. This is a real application process, not automatic, and it is where an attorney can help.
How to find out what is on your record
You can request your own criminal history from the state police so you know what actually appears, rather than guessing. If something that should have been erased still shows, there is a process to correct it.
An attorney can pull your record, tell you which path applies to each item, and handle a pardon application or an erasure correction.